First of all, confessing your love to someone you have only been talking to for two weeks is usually not the way to patch up a misunderstanding. Just deal with the misunderstanding.
Second of all, falling hard for someone within the space of two weeks may work for some people, but it rarely serves most guys well. Especially if they've had social challenges and are inexperienced in talking to females. You honestly sound like someone who is going to get burned.
Third, there are cross-cultural considerations. She's from Japan, and while I am not claiming to know what she actually thinks or what she is actually doing, you might be misinterpreting the way she is acting toward you for genuine boyfriend/girlfriend interest. Japanese culture is . . . different.
Again, I'm not judging her character or encouraging you to do the same, but the section from 5:48 to 7:10 could easily be pertinent:
I don't know if she likes you, is open to liking you, or is just being polite, or is simply excited to talk to a Westerner, or some combination of two or three of these.
Unfortunately, there's no surefire way to have success with that. What can be good advice for some guys is terrible advice for other guys. You need to assess yourself and think hard about who you are, and does whatever approach you are being counseled to take actually synergize with your strong points and your values and your personality, or is it the opposite? For instance, the pick-up artist community (PUA) approach is not really conducive to showing your best side and having a relationship with a woman who has Christian values. The guys in high school and college who did some of that stuff and appeared successful had traits that allowed them to temporarily get away with it. If you have to ask for dating advice on a forum, you don't. Likewise, the "don't pursue anyone and someone will become attracted to you" approach is terrible advice to give to a lot of shy guys, because they will double down on their shyness, and women in this culture are told not to pursue guys at all. So it's very good at keeping shy guys single. If I had a way to guide you to success, I wouldn't still be single myself, but I do have experience at taking people's advice and failing because I took it without really knowing how to make it work for me, or if it was even suitable for me.
First of all, Jeremiah 29:11 was God speaking to Israel about hope for the future after they had been taken into captivity. He still wanted to be their God even though their nation had been from their point of view, effectively destroyed. Second, Jeremiah was single for life, he was put in prison, put in stocks, thrown in a cistern, and saw the brutal sack of Jerusalem firsthand. His life was not a life that we today would call blessed. God's purposes are mysterious and are not always tied to a single follower's individual good. Sometimes God wants to give certain people earthly prosperity. Other times, he wants other people to take one for the team like Jeremiah. At very least, this situation can be a learning experience for you. I'm not going to say getting a wife out of this is impossible, but it is far from the only possible outcome that God would be OK with.
On top of that, she's not even a Christian, you must not marry her unless she converts. So you're looking at going outside of God's will in a situation where you would clearly need God's help to survive. This is foolish. Missionary dating - which at its core is dating someone in order to change that person - is for that reason alone, ill-advised. It's inherently disrespectful to the other person, just as if an unbeliever wanted to date you in order to convert you to her religion. Evangelism is good, but it and dating are at their best when they are not mixed.
So, how long have you been a Christian, and hold long have you been developing your faith afterwards?
Proverbs says other things about certain other kinds of wives. Make sure you really know what you're getting into with any woman, and with marriage in general. Crack open a Christian book on building a better marriage written for those who are already married sometime. You'll find that it's not all blissful sex and companionship.
You've peeled layers of that fear away. I don't think anyone can truly, 100% get over that, but I do know it can be greatly reinforced by what the opposite sex says and does and how you interpret it. When you are ill-equipped, that "let's take a chance on this" optimism will lead to getting burned.
