If Yvonne seems a bit aloof, it's not that she doesn't like you — it's just that she has to protect her secret identity.
Yvonne's always nice when you run into her — she compliments your hair, and when she asks you how you've been, it sounds like she really cares. But when you ask her how she is, you feel like she's holding something back. And when she disappears for four months, only to say she's been "traveling," you know she is. Maybe she has a secret boyfriend, maybe she's a spy, like Natasha — and maybe she's Batgirl.