He appreciates that she takes it. That she slips it on without a fight — because she's right. He doesn't have it in him to fight with her. Not now, not so soon, not her. Her wearing this is the closest thing to compromise they're going to get, all things considered.

For a moment after she dons it, it's quiet. Her looking up at him. Him looking down at her, something like conflict etched into the lines of his otherwise resigned expression.

At length, he nods once — at her, at it.

"Don't take that off until this is over."

This. His mark. His issues. His whole... deal. What over means, exactly, is up for interpretation. She can read it as until we find a cure. He means it as until he's out of the picture.

He's already got plans. Already laid the groundwork for it. The last favor he's ever gonna ask from Geralt, who's already been prepped to deliver it for months now.

They just gotta get him back first. After that...

After that, the problem's getting solved.