[his smile relaxes a little bit when he notices that, looking rather pleased with himself. but in regards of whether she should trust them or not, well. . . technically, he's one of the phantom thieves he's talking about, but can't actually say that? that would be bad?]

They're good people. One of their first targets was an asshole teacher that was both abusing and sexually harassing his students. They managed to get him to confess in front of the entire school, actually. And it escalated from there.

[aaaas for her second question:]

Quite frequently.