In case you needed a visual, this was Snow’s face during Hook’s confession.
Why is this so important? For one, they flashed to her face first, not Emma’s or Charming’s. The other two would have made far more sense: Emma is the one Hook loves, and Charming is Hook’s new buddy. No, they chose to show Snow’s face. Besides Emma, no one knew about Hook’s romantic past, the real reason he despised Rumple.
Snow didn’t know this, she had no idea Hook had been harboring this pain. I’m 95% certain up until this point she just thought he was this disgusting waste of space pirate who happened to be kind once in a blue moon.
Now we all know Snow is forgiving. We also know she has a soft spot for those seeking love. Where does this place Hook? She’s visibly conflicted, since most of what she thought about him was utterly wrong. How could she have been so wrong about someone? How could she not have known he was harboring this pain? Snow practically has a 6th sense for these kinds of things (Ariel, Regina, Emma, Grumpy, so on).
I just felt like she felt awkward, since Hook is basically embodying all the things she champions for: Looking for hope, being honest, knowing love when you see it.
Besides her emotional turmoil, from a story telling standpoint: Snow has been there for many of Emma and Hook’s interactions. The camera always flashes to her face when the three of them are in a room together. Why? Because Snow knows love when she sees it.
And that’s why she feels so awkward, since her biased mindset actually blinded her to something so obvious, and she doesn’t know what to do.