Why did Anne feel like she didn’t have a true friend?

Anne felt she didn't have a true friend because no matter how many people she called her friend, there was no one she could really talk to or confide in.

No, on the surface I seem to have everything, except my one true friend. All I think about when I'm with friends is having a good time. I can't bring myself to talk about anything but ordinary everyday things. We don't seem to be able to get any closer, and that's the problem. Maybe it's my fault that we don't confide in each other. In any case, that's just how things are, and unfortunately they're not liable to change. This is why I've started the diary.