I believe (no pun intended) I know exactly what you mean. You want to know for certain that your "belief" is what the Bible means by "belief". This is hard to answer but let me give some food for thought.
1. I think you are overthinking alot of this.
2. Lets assume the worst, lets say your belief is not "saving" if you will. It can become true belief. Check out John 4. Look at the example of the nobleman's son. The man sort of believed initially, then he truly believed after his son was healed.
3. Ask yourself this question: If a man pointed a gun at me would I deny Christ to live? If you said No then that at least shows you value Christ more than your own life. If you said Yes, Peter denied Christ 3 times so do not be afraid to be honest.
4. GOD KNOWS YOUR HEART BETTER THAN YOU DO. If you read this, read it again, until you get what that means.
5. Peolple are praying for you and your salvation. God will hear their prayers, they are in his will (save everyone, none perish), if believers pray for something in God's will, it generally comes about
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6. God sees your heart's heart if that makes any sense, your Father will see that you want to want to come to him. Remeber God abounds is grace and mercy triumphs justice. These are all things counting in favor of you.
7. Critical Point: He wants to save you. He is on your team and he wants you on His. He knows that Amandita would be a very nice Jewel in the Kingdom, He is very jealous for you, very jealous.
8. If you have not (I presume you have), pray for Him to make you believe in Jesus the correct way if you are not currently doing it correctly.
9. God knows what you want to do. He knows that you have a heart after him. Just like David and the Temple. Even though David did not actually build it, God saw that he wanted to.
10. We both know that deep down inside of you, you know that if you were ever in a desperate situation and you called on Jesus he WOULD do whatever would be best for you . That thing in the very center of your being that tells you you are never alone. Who do you think that is?
11. Alot of believers go through the same struggles, I do, Thomas (you know the Apostle) did, Peter (who said Jesus WAS the CHRIST before denying him) did, Phillip had been with Christ all that time, and still did not truly believe, nearly all of the disciples did not believe in Jesus in the "correct" way or else they would not have given up hope at his death.
12. Still dont believe that people have struggles (but eventually succeed) in proper belief? Look at Abraham, "The Father of Faith". He constantly doubted God but ultimately when put to the test he succeeded (as God knew he would).
13. You can think of belief as the intent of faith. Its said that belief comes from your heart (and thus core of your faith). So if your faith (i.e mental/spiritual assent without certainty) is in Jesus, and your intent is to trust in Jesus to be saved, then QED you must believe.
14. Point being, its not what type of belief you have, its what you do with it, and your intent (in whatever its current form is) is to put it into Jesus as your Lord and Savior. God sees that. Your actions outside reveal your inside, and with your persistent worry, that shows that you are genuinely concerned about this, because you take it seriously, and thus show that you do sincerely believe even if just a little bit. Satan is just trying to stop you from being effective for God.