There's a flash of indignant frustration that he calls it good, but the rest of his response soothes her. She looks down at her hands, fidgeting for a moment, then meets his gaze again with a soft look. It's difficult, putting herself out there this way, but Arthur's reassurance makes it easier, reinforces the behavior that much more.

"It won't happen again," she seems determined, and she goes on to explain. "Not on accident. I won't … I won't fight anyone else until I know exactly what I can do. I'll train, and I'll -- I'll get better."

It means more than just apologizing. So, she figures she can get away with it. She isn't interested in saying she's sorry again -- he knows that, and he seems to be past it. But, she can amend her behavior, make sure it doesn't happen again. She can try harder, do better. She can show that she means it through her actions. She can swear that much.