"Is that a problem?" It doesn't seem terribly unreasonable to him. Difficult, maybe. But humans change their minds all the time.

And if he's being honest, he has a great deal of respect for Toriel--more than anyone else on the Moira. He didn't expect it, but he felt the loss of her esteem.

He doesn't ask that she like him. She has very good reason to dislike him, after all.

But the reasons he has that respect for her are the same reasons he believes that she might be persuaded to reconsider.