"I -- guess I'll find out." Her grin is crooked and her laugh is quiet, but it's all completely sincere. You might as well stamp her heart with the words "property of Billy Kaplan."

She takes it seriously largely because she just wants to. Because she's spent a long time without family and with zero expectations of ever finding anything resembling family ever again -- and being offered the chance by a kid as sweet as Billy is... it's too tempting to pass up.

Really, she's glad he's not laughing at her in turn. Since he could assume she's being kind of crazy and tell her it's not such a big deal and not to take it so seriously. But he's rolling with it, which means he's okay with it... right?

Either way. It makes her feel just a little like she has a place to belong again. A feeling she thought she'd never get back.