From what you report it seems that your relationship is based on a one sided commitment. The girl you want to marry seems to be unsure of her feelings not only towards you, but otherwise as well. Besides love, mutual trust, respect and commitment are essential aspects in any relationship. However in your case the girl does not seem to be in love with you and she has even expressed that to you. Marriage is a life-long commitment; think about it, whether you want to marry someone who is unsure of her feelings and whose feelings even you are not sure of!