She said she didn't want to date you because she didn't want to ruin the friendship, yeah? Well by your description it's on it's way to ruin so what has she got to lose by giving you a chance?
If this is tearing you up so much I say you lay your cards on the table with her. Tell her that trying to hide how you feel is tearing you up inside. Tell her the friendship can't continue like this, which she has already acknowledged. With that in mind, suggest that if her only reason for not dating is the friendship ask her to consider a date maybe adding the ultimatum that you can't just be her friend anymore.
Good luck man.
'People are never perfect but love can be. People waste time looking for the perfect lover rather than creating the perfect love' - Princess Leigh-Cheri from Still Life With Woodpecker.