“Help! She Has Permanently Friend-zoned Me”

Help advise a confused soul:

My best friend who i have been asking out for over eight months finaly
told me “NO” on the 31st of December 2015. She made me promised her that
no matter what anwser she gives to my request, she will stil be my best
friend. But it has not been easy to keep to that promise, although i
stil love her and she claims to love me too but can’t date me due to
reasons she has not clearly stated. A part of me is even glad she did
not accept me because she has an ‘unforgiving spirit’ . My problem now
is that i cant stop loving her and if i keep away from her i will be
breaking a promise. How do i move on without putting her away? She once
said that all the guys she has turned down are now her enemies and wont
want me to join that crew. Pls what do i do? Thanks in advance