to me i think his answer has to do with the change in his mother, earlier in the movie when she is visiting him they talk about the scar on his arm and he says its the only honest thing you ever did, to me he seemed to always be trying to get a reaction out of her, he knew that she resented him she even said it to him as a child i could be in france right now instead she is with him, i always felt like he was trying to get her to admit that she hated him and her resentment towards him cause him to resent her to the point he wanted to make he suffer, but after he murders all those people and even when she is suffering the way he wanted she still came to see him all the time, he gave her the chance for her to truly show her hatred towards him but she didnt and i think thats what made him question his reason for doing it also i think it was his last test to see if she would finally say it but instead she hug him

I think his answer has to do with the change in his mother, earlier in the movie when she is visiting him they talk about the scar on his arm and he says it's the only honest thing you ever did.

He seemed to always be trying to get a reaction out of her. He knew that she resented him she even said it to him as a child I could be in France right now instead she is with him.

I always felt like he was trying to get her to admit that she hated him and her resentment towards him cause him to resent her to the point he wanted to make him suffer. But after he murders all those people and even when she is suffering the way he wanted, she still came to see him all the time.

He gave her the chance for her to truly show her hatred towards him but she didn't and I think that's what made him question his reason for doing it. Also I think it was his last test to see if she would finally say it but instead she hugs him.