Zuko hesitates, but she doesn't think Ryu would suddenly hate her for admitting it. She's convinced at least some of the Bastion would, of course, but not Ryu.

And besides, with Toph here, the other girl might wind up mentioning it off-hand. It's farther in the past for her, and she never witnessed Zuko at her worst first-hand.

"I spent most of the past three years hunting the Avatar. The one person who could restore balance to our world. I was willing to do anything for it."