[ He knows exactly what she means, but even at this stage, not aware of his near future from first-hand experience, he's almost certain that they can trust her. ]

Lydia can be a lot of things, but she's... [ He doesn't want to say pack, he really doesn't, because she's not, not really, but she is an ally, even if it's been an unwillingly one as far as he's experienced. ] We can trust her. If she'll help, she'll understand we need her to keep it to herself.

[ He thinks, he hopes, but they've got Stiles on their side, and what they could find out from the book would affect people she cares for if Jackson and Scott count for anything.

Looking to Stiles. ] After Jackson, she helps us?