She said Buzen was the one who told her. That his existence is uncertain, and he wasn't sure if he'd still be there after his mission.

[he smiles, all teeth. isn't this what comes of trusting humans? (calm down rang) that buzen had spelled his own fate because he was confiding to a friend pierces through rang in a way that knowing she had just killed him because he was a sword hadn't achieved,]

She just wanted an easy target. Someone who wouldn't hate her. Because if she was really judging us by worth, then she would have targeted me instead.