[JET73L]

Try to see things from her point of view (mentally/philosopically. I don't mean specifically like an argument). You could even discuss this sort of thing with her, Miss Valentine seems correct in how, whether she thinks she loves you or not, being as deep friends as you seem, even/especially with the dating, that it may be a near-perfect fit. Just because someone doesn't believe in something, doesn't mean they don't feel it in their own way. If she accepts how you (think you) feel, it may be okay, but if she merely disregards your belief in love, it may suggest deeper problems and the refusal of accomodation (if this is the situation) would just be an outer representation of a more important disagreement, that you may or may not have noticed and probably have not discussed.
Either way, if it's cool, just surf it out, and don't try to duck out halfway through a killer wave. You would probably end up falling from one side, or getting hit by the whole wall of water.

PS: if I don;t make sense, disregard whatever I've said. I can be overly cryptic on accident. And even if it does make sense, I may not be the best to take advice from, considering. That was just my suggestions.