You said that you were geniunly interested and I believe the first thing to accomplish your wish is to clear your mind and think about everything as it comes. In other words no pre planned mentality and no “I will not agree unless it is what I believe in”.
Now first of all word "fundamental" is wrong. Would you rather have a doctor operating on you who knows fundamentals of operating proceedure or someone who is not aware of it? Perhaps you meant extremist, but still I would not agree with that as this word again depends on how and where you use it.
////After all you assert that we are all born sinners//// That is where I say that you need to study other religions yourselves instead of depending upon a handful of websites. Islam does not believe at all in that and I believe even Bible has verses nullifying this concept. Every human is answerable for his/her own actions. Then in Islam the concept of hell is not “forever”, it is a transitional somewhat like a prison where you go, serve for your bad doings and be released.
OG has already answered your question about whether it is love or fear. I believe every love has a fear factor behind it. Fear of losing that the one you love or the one who loves you.