Cesare knows some of her past. After being caught off guard during their first meeting, he made a point of finding out about her. He knows she's a fighter, but still...

"I'd suspected your time with witches might have tamed you. They certainly seem content on taming us." And by us, he mostly means himself. For some reason, he's taken a rather extreme dislike to the witches. In his eyes, they hold too much power that they insist of wielding against others. Cesare doesn't like it, though that could be because he would rather be the one with the power himself.

"But here we both are," he echoes, lifting his glass in toast. Well done, Natasha. Respect for not being so easily swayed.