The trust doesn't need to be spoken. It's been there since Clint saved Natasha and Phil backed his call. They can look at each other and know, like a string tying them together, the trust is there.

"We'll scandalize the junior agents." Which could be really amusing, actually. Phil will enjoy everyone's jaws dropping as word of their relationship spreads.

"Next you're going to ask for a pat on the ass like we're football players in the locker room."