Why do you feel sad?
He could sacrifice even more for her but, he didn't ask for her opinion if she really wanted to do what he wants her to do, knowing that girls like her tend to shy away from important things. That was his only concern and it is the main reason for him to even lock her inside the house.
Though he saw her progress he still wanted to test her in-person to know if she was capable of remembering them all. Though the time was limited, he felt that 45 days were a lot for her. And just reading books was utterly useless so he wanted to test her with real-life situations.
He looked at her with a sad face, looking at that she couldn't control her emotions. Even now she cried a lot, the only thing that he could do is to see her cry out her eyes all time. What else should he do? When he planned to be ruthless, he couldn't just stay in a faraway place and look at her weeping all day.