How do you cope with a well-gaurded woman who appears to be interested in you?

I recently met a wonderful woman about a month ago on a popular online dating site. Our initial phone conversations were great and we would talk for HOURS at a time (and we still do). We felt like we had known one another for years! We have so much in common too! She warned me up-front, however, that she works very slowly with regard to relationships as a result of a previous five-year-long committment that went sour about a year ago (she refers to herself as a really 'gaurded woman' since then). I re-assured her that I would not place any pressure on her and that she may take as long as she needs to get comfortable with me. In the meantime, we chat on the phone almost daily, but she APPEARS to be hesitent about meeting in person (we met twice before in person). She claims she wants to but always has a reason why she can't. In previous conversations, she told me to my face that she is not pursuing anyone else and that she is interested in me. She seems to me to be a straight-shooter and not a game player. As a 33 year-old, mature, professional, independent woman, I would think that game playing would be out of the question for her. Do you think it's normal for a 'gaurded woman' to act this way? I don't have any experience with this. Please help!!  :)