It seems that she really cares for you, it's really sweet. =3
Anyway, about your problem. Are you a hundred percent sure that she is talking about you? Maybe she's trying to tell you that she has a crush on someone else?
But if she is writing about you, then tell her how you really feel. Tell her in a gentle, gracious, and understanding demeanor. Just be really kind and sweet about it. If she really loves you, as a friend or more, then she'll understand how you feel and accept it.