Here we go again! in love with a best friend...help needed!

Ok so I have known my friend for around 6 years, anyway, i started having feelings for her two years ago and we had a one time friends with benifits, after that i told her i had feelings for her and they were going stronger, she told me she was proud of me telling her how i feel and that she would never leave me, because we discussed this and we said it wouldnt destroy our friendship, however my best friend told me she felt bad because she didn't feel the same way and knows how much it hurts, but she told me she will always be there for me and she would never hurt me

I realise How lucky i am to have her as a friend because i hear most friends with benifits relationships never end well and normally the other friend freaks out, but she is different she listens to me she is a true best friend who will never leave me.

I am wondering if it is possible if she could develop feelings for me overtime after what we have been through together, because i know i will probably have feelings for her for the rest of my life since i talk to her almost everyday. I am just wondering if she would ever fall for me? how would i get her to fall for me??

please help much appreciated
thanks :)