Max still has concerns, but they're things he can't explain to her any better than he could to Furiosa. However, he can't just wash his hands of it like he would have if they were on his world. He does care what happens to her despite himself, and they're together on this voyage.

"Good." He'll take her assessment and believe it. (It helps rather a lot that Tommy really hasn't done anything to validate Max's mistrust. He is less watchful now than he used to be; he's willing to let Tommy stay at his fire, in fact.)

"Happy doesn't happen around here. Not for most people." He's glad that she's happy is what he really means to say.