He actually said it. Out loud. To another human being.
Strike that, to Misizu.
It's a start. Now go off and practice saying it some more, Jun. Walls, bowls of ramen, Carol, other inanimate objects. You need to work up to it, boy. Ganbatte!
I mean, Jun is one of the densest motherfuckers alive but even he knows why he should be having this conversation with her more than some of y'all. It's not like Misuzu's internal monologue for like 400 chapters is letting you know or anything.