He's acting strange. Stranger than she would expect someone who encountered an enemy, former enemy, or ally from their world. No mirth, hedging his words, reaching for her hands.

It's all cause to watch him far more carefully than she'd been watching. He tells her of his vows when he was with the Watch, no wife and no children (might've been amusing under other circumstances that he's so adamant about her ability to have children). It might've called far more questions to mind, except--

"Become one of them," she repeats. Her gaze lowers to their hands. Rather obvious, when he frames it all that way. So a past lover's returned into Jon's life, is that is? When she looks up at him, she lifts her chin. "What does she expect of you?"