[... Ha. Well. Minato can't say he's entirely surprised by that statement. With everything he knows about Izuku and what he's been through...?]

... It can be hard sometimes to believe in yourself, I think. When... you've been through all of the things you have.

But that's okay.

[He nods peacefully, firmly, and:]

For those times... when it's hard for you to believe in yourself, I'll believe in you. Until you can believe in yourself again. It's a promise.