Anonymous: something could happen and she'll either reject you and embarrass the crap out of you, or do something with you and keep YOU a secret because shes not comfortable with her sexuality IF shes gay (fat chance). And if you don't want to tell her then move on because you CAN'T be friends with someone you're in love with, PERIOD. Especially once you'll have to start seeing her with someone else. Save yourself and pick one or the other. Either way, get out of the friend zone!
Anonymous: terrible break up in which I got cheated on and I went out to LA with him and got drunk. One thing led to another and BAM after two years of being my best friend something happened. Now heres where my situation hopefully differs: the asshole keeps seeing me and keeps all of it from his girlfriend. So I left to Argentina to move on. Theres more to the story but its irrelevant to your situation. Bottom line: you need to either tell her or stop knowing her altogether. If you don't tell her...