How do I deal with this?

Okay so there is this girl I like but I don't think she likes me? Idk, I don't want to ask her out cause I don't want to ruin the friend ship, I mean I just have been friends with her this year, and I don't think she really likes boys from all the crap her other boy friends put her thourgh, so like what should I do ask her out or just remain quiet and let her slip by?