"I would feel safer with you there." Because he does still believe and trust absolutely that Clint wouldn't hurt him. Now that he's free of Loki's influence, he wouldn't hurt him. Clint even said he adores him. Still.

"Safe enough that the gun can go somewhere you think is safe. If you're willing to try that." Phil's not promising anything more than a night of sleep because Clint's clearly still skittish. But it could be a start for both of them.