First of all, the Bible doesn't say that you have to hear God speak to you specifically or get a specific sign to get married. There are a huge number of people who are eligible marriage partners out there. Is the other person a believer? Is the other person married? (or is the other person Biblically ineligible even if they are legally divorced under state law?) Is the other person a close relative or a widow(er) of certain close relatives (e.g. one's father's widow is off limits.)
If not, it isn't a sin to marry that person. Like Paul said, "If you marry, you have not sinned."
Generally it isn't a sin. If the Lord directs you not to marry someone and you do, even if that person would otherwise be acceptable, that is not a sin.
Another issue is marrying in an honorable way. I saw in the Old Testament that fathers gave their daughters away in marriage. This may be referred to in I Corinthians 7 depending on how you interpret the passage about a man giving his virgin in marriage. It was important to me to get my wife's father's approval before getting married.
That being said, I think it is wiser to seek direction from the Lord about marriage than to just get married to someone, especially if you live in a culture where you are expected to date and choose someone who seems suitable.
Here was my situation, or part of it. I was praying about finding my wife. I wasn't wanting to date around until I found her. I was living in Indonesia, and a missionary invited me over for dinner to his apartment which was on a Bible college campus, during Christmas break. He said I should come by and check out the English books in the library some time. I thought it sounded like a good idea. It was pretty close to my house, too. I went up there to make friends, and had a look at some of the books. Probably the second time I went there I met my wife.
My wife was leaving the cafeteria area downstairs below the library and sensed the Lord wanted her to talk to me. She said to the Lord she was a shy Asian girl, and didn't want to approach a man like that. So she tried to figure out how to do it. I was talking to this guy with a guitar, one of her classmates. So she asked the guy, Philemon, if he knew a certain Christian song. I struck up a conversation with her. She had a word of knowledge/prophetic word for me. I gave her my phone number but forgot to get hers. I figured I'd call her about that word.
There was a connection I could sense. I went home and asked in prayer if this was the woman who was going to be my wife. I didn't know this until we were engaged and she let me read it, but she went home and wrote down in her prayer journal, "If it's your will, give me to him, and him to me." She had a sense we were meant to be together, too.
I would have liked to have had someone prophesy we were meant to be together. It was almost like the opposite occurred. After a while, we started hanging out as 'friends' all the time. I'd pick her up after work and take her out to eat every single night and walk her to the door of her boarding house. We'd go to church together. We'd see each other every day. Eventually, I felt like I was lying by just saying she was my 'friend.' I didn't realize Indonesians did this all the time right up until their engagement. But she'd call me 'brother.' I didn't know Indonesians do that when they were dating, so it felt like she was emphasizing the 'just friends' status we had discussed. Neither of us wanted to date before we met our future spouse, and I didn't want to have to get engaged to date her. We eventually got over our miscommunication. She eventually agreed to let me call her my girlfriend without actually proposing, and I stopped feeling like I was lying.
So how did I determine this was the woman the Lord wanted me to marry? Well, when I wasn't taking my future wife to a church service or out to eat or talking to her or whatever, I'd often spend time praying about it. It seemed as if the Lord were speaking to my heart when I asked "Is this the woman you want me to marry?" It sure seemed like He was saying "Yes." And when I'd pray later on, it sure seemed like He was saying
"Yes. Why don't you believe me?"
And there were a few other things. Maybe a year or so before I had that first conversation with the woman I would marry, a female friend of mine said she'd had a vision of my future wife.
I went to prayer and told the Lord that the Bible says "the secret things belong to the Lord, but the things that are revealed belong to us and to our children forever."
I argued my case. If the Lord had showed my wife to someone else, He'd already revealed it. It wasn't a secret anymore. By rights, wasn't that knowledge mine as well? So I asked him to show me my wife. I had a vision then. Not one of those 3-D looks like real life, looks, feels and smells like you are there visions, but a strong mental picture in my mind. I don't really think in picture much. My dreams are like cartoons are paintings.
This vision started out zoomed in on an eye and eyebrow. It zoomed out to a woman's face. The face was a bit shiny like it was oily, and boom it went away. I didn't get to look at the face and memorize it, but I certainly remembered the experience.
So when I went to my future wife's boarding house one time, she let me see a picture of her when she was younger--before she started plucking her eyebrows, and I thought, now that looks like that could be the woman I had the vision of. My wife's eyebrows didn't look like the vision when I met her, but her original eyebrows looked like that. And the skin on my wife's face can get a bit oily.
Also, there was something very personal about my wife I won't share. But I asked a question that made her upset on the phone. I prayed about it and sensed the Lord telling me something about her. We talked later and she told me a story which was what I had gotten in prayer and that helped encourage me along the way.
My wife had also seen a vision of me. And many years before, she'd gone to a 'prayer mountain' retreat home where an African man said that God had spoken to him in his ear. She had gone there asking if she should go to Bible college and go into ministry, if she would meet her birth mother, about her future husband, and something else. His prophecy hit on all four things she had prayed about, including when she would meet her mother. He said that her husband would be a missionary. I was an ESL English teacher overseas, not sent by a church, but her prophecy she got from that man was something to goad me into my call I suppose. I got more active in teaching in churches after I met her. It was a process the Lord was working in me.
So during this time, I had a couple of men older than me speaking into my life. One was letting me stay in the house he was staying in, his sister-in-laws house actually. He was about 40, married, with five kids and went to my church. He told me when he wanted to make a decision, he'd read the Bible to see if it gave direction about the decision. He'd pray to see if He heard anything. If He did, He'd go with that. If not, he'd pray, "Lord, I'm going to make this decision. Here's why. If you don't want me to do this, stop me."
I talked to a missionary who used more or less the same method.
Not making a decision is a decision, too, you know. We are allowed to make decisions. We just need to acknowledge the Lord in our decisions and trust Him to guide our steps.
So I did that when my wife was on a short-term missions trip. Up to this point, I was maybe 90% sure she was to be my wife. But I knelt down by my bed in the boarding house I lived in (not my wife's boarding house, btw) and prayed. I told the Lord the reasons why I believed He wanted me to marry her, and said I was going to go buy a ring, and if He didn't want me to do that, to stop me.
I had peace about it then. I was 100% sure. I had made up my mind. It was going to happen. But we had some opposition from family on her side, in her extended family collectivist culture, and obstacles like that to overcome, but it did happen and we got married about 5 months later. A day or two later I went to pick my wife up at the train station after her missions trip. I had arranged to have an older gentleman from church go with me to pick out an engagement ring the night before my birthday.
I would have loved to have had a prophecy confirming what I thought I was hearing before I decided to get engaged. After I'd decided to marry her, an evangelist from the state I was from, whom I'd met before I met my wife, was back in the country. He called us up after preaching a sermon and gave us a prophecy about the Lord sending us to many places to minister to many people-- which implied we'd be together for a long time, and hence likely to be married. I told him later I was getting ready to buy a ring. He said he thought it was probably time I did that. I asked him if he was nervous about giving prophecies like that. He said he used to be.
It was a real encouragement. Before all this, I asked the the woman who said she'd had a vision of my future wife what she thought of the woman I would eventually marry, and she said it didn't look like her vision. I had been praying a lot and I believed I was hearing God, but my wife sure didn't like hearing that. It was an obstacle to overcome. This woman was about 30 and unmarried, and had commented on how she didn't think people were supposed to be together on other occasions. She had this idea that everyone could only marry a specific soul-mate or something.
We got some other confirmations about our marriage, btw. Two or three people in Indonesia kept telling us this word about the threefold strand, that with Christ, her, and me, we were like a threefold cord-- from Proverbs. It is not easily broken. Then we went to the US to a wedding party at my parent's house and the assistant pastor who was prophetically gifted who prayed a blessing over us got that same verse. There were a lot of little things like that, prophetic words where people didn't say 'Thus saith the Lord' that we could perceive were from the Lord.
I do believe in mine and my wife's case, God had chosen us specifically for each other. I'd asked the Lord to do that, after reading the story about Isaac and Rebeca, to send an angel before me to find me a wife, and things like that. While God can direct us specifically like this, He can just have people get married based on His sovereign providence. If you choose unwisely, you still need to honor the Lord's instructions about staying married, not divorcing, not committing adultery.
If you'd like to have a lot of confirmation from the Lord, direction, that sort of thing, pray specifically for it and seek Him for it in faith. We've got all these incredible promises about what we can have if we ask, seek, knock. James says you have not because you ask not. So if you want direction from the Lord, pray and ask. But on the other hand, don't be unbelieving or fearful about getting married. Once you find the right person, a lot of times its worth it to go ahead and get married. Your life may actually be more productive because dating and spending time thinking about whether you should get married can take time away from some of the things you can do when you get married. Celibates may have opportunities to be more productive than married folks, but a believer remaining celibate who spends huge amounts of time dating and trying to figure out what to marry probably isn't as productive in this way as those who are settled in to celibacy. If you've found the person, marrying prevents a lot of the temptations you have to struggle with after you've found someone you love who you want to marry, but who you aren't allowed to be intimate with.
Anyway, that was long. But that was my story, an abridged version, of how the Lord directed me to marry and my thoughts on the subject.