Told her i love her but..?

okay im in love with my best friend that has a boyfriend and after a very large argument with her i told her the reason im blunt and unresponsive at times is because i love her and think about her all the time.. it hurts to think of them together!! okay so i told her4 that i was in love with her and she said "its okay, i wont think of you any differently, im not like that!" and "we'll be fine, honestly its okay" its like she has no trouble moving on from this and it'll be easy.. its been a while now and ive been putting a brave face on but its getting harder and i just wanna give in but i know from previous experience, love cannot be undone.. we are such close friends, it would be a shame to lose that.. what should i do, how can i get her?! or how can i move on from this with my heart intact and not shattered?! :( please help me?