SO MY BEST FRIEND AND I...?

We've been friends for a few years now. we have just recently grown very close. We attend college together and are the same age. She is everything i look for in a woman but here is my problem. I was heavily infatuated with her best friend for years and it caused a lot of problem both for me and for her and now we arent speaking to one another however my best friend was there the whole time. My Best friend and i have since talked about this and she felt as if when i was around this other girl she wasnt important to me. we talked and i told her that wasnt true that i valued her always being there. She has told me of problems in her past with guys it always seems that her friends are the guys that end up liking her and its hard for her to be friends with guys for that very reason. but we have grown very close and i have developed feelings for her knowing her fears of this i am trying very hard to hide them, my parents and several friends have told me that they think that we would be great together but i try not to think about her that way because of what happened with her best friend i dont want it to happen again i couldnt live with myself if she stopped talking to me. I am beginning the stage of my life where i am really starting to feel the need to find someone to be with and she has told me about how other guys have been making advances toward her it makes me feel very jealous and protective but she has said that shes beginning to warm up the idea of relationships in general not necessarily me. she speaks freely to me about relationship things. i really feel like she could be the one that i spend the rest of my life with i just dont know how or when to tell her how i feel about her or even if i should... She is afraid of all her guy friends falling for her i know this we have talked about it and have been observing boundries to try and prevent this but it happened and it feels pretty big to me. i know that she and i would be great together we have the same faith same values we share the same goals and we challenge each other to be better people i can see myself 50 years from now happily married to her but i am not what she looks for physically in a man and that thought intimidates me. i know how i feel i would marry her right now if i thought she would. how do i tell her how i feel about her? should i risk losing her entirely? if i should then when? please help me out. thanks.