If they knew how much she'd taken from such a simple statement, maybe they wouldn't have said it at all. As it stands, she... assumes, to an extent. Extends her appreciation and compares it to their own, willing them not to contest that.

In this, one context, they won't. For the one, rare instance of feeling that someone has seen and understood entirely- beyond what Frisk could, beyond what Tim could, taken in the very worst they had to offer and found things in it that could almost be called a comfort, they can hold their tongue with...with ease.

Because at this moment, knowing her soul, they might even have to believe that. Their lips curve into a crooked smile as Chara drops their gaze, comfortable enough in her presence to not keep a constant eye on her, for the time being. Maybe that's not much, but

Just the ability to sit quietly for a while is

Nice.