From what I understand, if a woman likes you (that way) you'll be able to tell. If you think you're getting mixed signals than my guess would be she doesn't.

I can't speak from experience, keep in mind, but apparently some women will keep a guy in the friend zone, even if she's interested in him sexually, because she's waiting or holding out for better. If that doesn't happen, she then thinks she has a decent guy to "fall back on".

If I ever believed a woman thought of me in that way, I would probably cut ties with her, that's just me.