He may not be showing his fear, but that doesn't mean Garth'zel can't sense it.

"Child, I'm not him. I'm not going to hit you," Garth'zel says gently. "Yell at you sometimes, yes. Punish you by sending you to your room and things of that nature, yes. But not physically hurt you."

Something it'll take Anakin time to be able to believe, he knows.

He shakes his head slightly. "Aside from a couple of things I'll want to check before I go to bed, that sort of thing is done for today. I can point you at things tomorrow when they need doing. Some of it won't need anything more than just making sure the indicator lights and so on are where they should be, others will actually need some work done, even if usually no more than about five minutes' worth."