"Was he kind, this man?" River asks, because she doesn't want to disregard her understanding. The Doctor isn't unkind, perhaps selfish, but not unkind. And River knows that.

"It's fine, sweetie," she says gently, and she finds that she means it. "Yes. I was safe."

River smiles, though it's faint and doesn't quite reach her eyes. "He left me in a library, with every book ever written. I guess he expected that would be enough. He was young then."