Your father was always neglectful towards you. He never really cared about you, never praised you. And when you did talk he would just yell at you, his words always hurt. So once you got to U.A. Thing were different. Over time you started seeing aizawa as a father. You would vent to him about your father, cry to him in his arms and he’d comfort you. You’ll tell him things he might forget so you tell him again which you don’t mind, he just listens and it feels nice. It got to the point where he started seeing you as his own daughter too.