Let me put it to you this way man.
Either she really is too busy, she is scared to put that commitment in her life, or (at worst case) she is messing with your head because she thinks she can get away with it. Regardless of her reasons there, if you heard she likes you through the grapevine then it probably could be true. However it seems like she isn't willing to make sacrifices in her schedule, put herself on the line emotionally, or give you the respect of not messing with you because she feels like she's already got you hooked. She controls the pace of things because she knows you won't do much about it.
Even though you've confronted her, you need to take a big step back. Walk away and focus your interest on other women. If she has enough interest in you then she will pursue you after you've gone, because she'll realize that you weren't someone that she could drag along the line forever and will take risks in her life to get you back.
Women pick up when a guy is reeled in to the point where they can get away with anything. The reason why the "bad guys" seem to have better success with women? Because they don't chase the women, they let the women chase them.
(Obviously I'm not implying that you should do the same things she did to other women you meet- I'm just saying when you have the ability to move on, that's when the prize catches come in.)
That was a rather complicated explanation of my take on the situation... I hope I wasn't too confusing.
Good luck man with finding that special someone. It's an uphill battle both inside and outside, but if you keep your wits about you, then you WILL make it!