She thought he didn't trust her? That was ridiculous, of course he trusted her. Just because he didn't feel the need to dump all his problems on her didn't mean he didn't trust her.
"You really want to hear about me missing Mum or how Dad didn't find having two children who needed him good enough reason to not kill himself? Or how Jennifer is too busy with her own perfect little family to visit her brother on his birthday even though I always go see her on hers. So didn't even owl to say Happy Birthday or anything. Not that that matters since I don't like birthdays but it would've been nice. Or how we lost quidditch? Because I don't think anyone wants to listen to all that." Or how he was pretty sure he was still in love with his ex girlfriend who was getting sent more presents than him despite it being his birthday by some random guy. That wasn't really an appropriate thing to bring up, however so he didn't. Instead he just gave a brief outline of his current issues. She wanted him to share his problems and he had. She'd better not expect him to go into more detail because he did not want to do that.