"It's so sweet you don't even know how sweet it is"

Ace is at the kitchen table putting together his lego firetruck and Julia is watching, this is the conversation:

Julia: I like your firetruck Ace.

Ace: I know. It's awesome.

Julia: Yeah, it's awesome.

Ace: And sweet. It's so sweet you don't even know how sweet it is.

Julia: Yes I do.

Ace: No, no you don't. You don't even know.

Julia: Oh. It's awesome?

Ace: Yes. And sweet.

Julia: I know.

Ace: No you don't.