I think the most important question here is would you still want to be friends with her if she has no romantic interest in you, whatsoever, and no chance of sparking any such interest.
If you can answer that with a yes, then just tell her that, and if she doesn't feel like that about you, then you still have a cool friend.
If your answer to that question is no, then wouldn't you like to resolve this issue so you can spend your time stalking someone else (you creep)?