If they were judged by the law then their reasons would mean very little and they would be judged by what they had done and the severity of it.
If Ash chose to listen to him properly and believed him, she could not know for sure if he would do the same again if given the chance.
He had already seen her face and knew of her identity along with having a memory of what she did to him.
Even if he was able to put it behind him, he could tell anyone about everything.
What made it even worse for her was that he knew where she lived so she would risk exposing where she lived if she did let him go.
If there was ever a day when she needed to get ahold of him again, the same tricks would not work on him anymore since his vigilance would be raised by a lot and he would take more precautions to protect himself.
Ash simply had no choice but to go through with everything the moment she brought him to the building where she was living.