How does a girl get rid of hatred towards a young man who deceived her, when she sees him every day?

If the young man is disobedient and far from Allah, then your hatred for him is correct, and the hatred should be proportional to the sin. A Muslim should not be hated completely as long as he possesses the foundation of faith. Love for the sake of Allah and hatred for the sake of Allah are among the most complete characteristics of faith and its firmest ties. However, if your hatred for him is due to his lineage or characteristics unrelated to religion, then repent to Allah, for it is a right of a Muslim upon another Muslim to be respected and honored.