This particular discrepancy is at least abstract enough not to bother Emma. For all she knows, Holly's world just thinks the world is flat still. Welce did for centuries, after all. It has not turned to silver in front of her. She is allowed to giggle.

But also- she feels bad. It really is a very different world. She wants to be welcoming, on behalf of her world, or something?

"Sorry," she says. "I know you sad, want your world. I just- I know, your world good, but I want you think my world good also."

They hadn't actually gotten to 'also', yet, but hopefully it's reasonably obvious in context. Maybe.