Shes saying "I like you, but I dont know enough to trust you."

She could be worried that there is something about you that she doesnt know about ie. your a date rapist.

Give it a chance, and probably after about 2 dates she wont want anyone else there but you.

If that is not the case, then ask her whats going on. She could just like you as a friend, or maybe she doenst like you at all, but is too nice to say anything.

Just hang in there!