Cosette relaxes, without quite realizing it. He doesn't seem so sad now; he's cheered up, that's good.

(Cosette's father is a man of heavy sorrows and mournful silences. Cosette learned early that she couldn't mend them and she couldn't learn what was behind them, but she could cheer him and distract him, and that's her immediate and ingrained response to someone else's sadness. If she can cheer them up, it's all right, and she's helped as much as she could.)

"Centuries! Oh, it sounds horrible. I can't even imagine. I am glad you'll be together, my lord. I wish you all the very greatest happiness together, I do."