It sounds like he means it, and she wants him to--this much, she wants to be true. If anything Byerly says is worth hearing, let it be these promises: that he'll keep her secret, and that he'll make sure she stays dead. He seems serious enough, though she's still not sure that means anything at all.

"Okay." It's not the first time he's brought up Miles to her, and that seems like proof in itself that this might be real, inasmuch as anything is. (Or Miles is also inherently untrustworthy, but that wasn't the sense she got from him when they spoke.) If it ends up she has to take her chances in the wild, she will. For now, she'll try to trust him, and for later, she'll have her knife.

Which is where one of her hands settles now, not quite idly. There's one other thing she has to say, if she's going to trust him, really trust him, on this. Taking a little breath, she looks up at him. "You could've killed me when we came out here, but you didn't. Um. Thanks."