Your trust in her, perhaps. You should trust her anyway though - She's your daughter, you probably know her better than anyone and frankly if she's already untrustworthy by the time she's on the internet then you've either majorly screwed her up or you're being awfully bad about not letting her use a computer.

The more important trust, that you need to establish with her during the adolescent years where she's figuring out how the world works and where she fits in it, is her trust in you. That's not something that exists just because of DNA, contrary to many subpar parents expectations - It exists because you show her that she can trust you.

And again - trust is a two way street. The first step to her trusting you is you trusting her.