I am in love with another man's fiancee

I am a Fourth Year student at the university, and I am in love with a classmate (also my best friend) whom I have adored since we first met in 2010. She is, however, engaged but she says her relationship is wanting. She says she regrets having not walked out earlier. For a month now, we have been doing literally everything together (except sex) with the hope that she will quit the other relationship so we can start dating. Recently, I went through her phone messages and learnt things are as perfect as can be with the other guy. I have showered her with gifs and taken her out. I really love her and she says she likes me a lot, but I am not sure what I should do about this. Please advice...

{Desmond}