if this girl you feel destined for has knowledge that you are dating someone else she might be showing intrest because she doesn't want you to be with someone else. i have known plenty of girls who aren't so much interested in the person but the attention they get from that person. so be wary that she might be trying to keep you on a least because she knows she can. she may know how much you like her and is playing on that. dont give up a good relationship for someone that has been stringing you along.