Ignore her, if she likes you she will miss you and you can get her to admit it (I did it and she admitted it, so now she can't say NO, I didn't miss you). The thing though, is why you want her to miss you? Is she being hot and cold? If so this is the best way to go, because you will show her that you don't go around playing her little mind games. Some people will tell you "dont ignore her, that's mean!" but seriously, some girls need help growing up and all you are doing in giving her that little push she needs. You gotta be willing to do it for a while, a week or two, if she talks to you, respond, be polite, but act extremely uninterested, don't initiate any conversations. After you've done it, go up to her, talk to her like nothing happened, then ask if she missed you and you will have your answer.