"Oh well, I'll tell her next time..."
Given the nature of this manga and the type of spineless protagonist this guy is, this is never happening. He just doesn't have it in him.
If she's actually saying what he's thinking, then yeah the statement above was just proven true. But I somehow doubt that's what she means. I'm pretty sure she's talking about something else again and he's misunderstanding yet again. It's like they're almost never on the same page about something.
This time it was the childhood memento box. Let's see what's the next bait + misunderstanding they'll have next....