I'm in love!!!!!!!!!!!!?

I realy like this girl.we've known each other for the past 4 years,and only in 2007 i got closer as a fren.i realy like her,i mean she is so beautiful,plays dota(which i nvr known a girl dat does),she's smart,she's realy kind hearted,n a lot more.... but unfortunately,she has a boyfren,and he's kind of a good person.but i juz knw,dat she's the one for me.so what shoul i do? i'm scared if i tell her how i fell,i might lose her as a fren.