Geralt is rather astute even without his mutant enhancements, allowing him to hear that mess of memories that instantly get called back even if she didn't want them to. He almost feels bad for pressing it but when he's around Cassandra there's a draw to want to know about her. And more than what he was normally interested in knowing with someone.

"Worlds?" he looks at her again, keeping his gaze fixed on her side profile. "How many have you been to?"

He's barely accepted there was a world beyond his own. To know there were so many other worlds was something he couldn't fathom.