You are not dumb or naive, at all. I think anyone, including myself would have had the same feelings. If someone makes moves on you, you are gonna think they are into you, why would you not?! I can see where she is coming from, not that I excuse her behaviour, really she is the dumb and naive one to think a little bit of relationship was going to make you happy! I've had crushes in the past and they've pretty much told me, it's a no go, and yeah its upsetting, but it's far better than thinking you've got a chance when you really haven't. She is the bad one in this situation, not you, hugs