"But they did." Maybe that's why they can't say it. Why they can't just say I forgive you, and wash their hands of it. "In the best path. You come for me, and you save me, and I don't have to die. You stop Asgore. Everyone goes home happy."

That's not even the half of it. But in terms of her role in the events - it is. It's all that matters, in the end, because she did step in, and Asgore didn't want to hurt them, and she kept him from doing it.

All her fears, all her expectations...

Were they really for nothing?