"Naruto..." Families love each other. She always thought Naruto considered Sasuke to be his brother, so he did have one. Maybe Sasuke didn't agree with the sentiment but that never stopped Naruto before. She doesn't really expect him to admit that to Sasuke's face right here though.

Not in front of her.

He comes to the same conclusion she does -- they haven't killed each other, so that means something outside of Sasuke not wanting them to harm his brother. While irritated she still didn't know what was going on or the 'truth' (as Sasuke and Naruto have BOTH called it now), she had to be moved by Naruto's words. She wonders if Sasuke is too so she tries to read his expression.