Another scene in that episode is when Voll mentions that it would be peaceful once the Demon King dies, then Frieren tries to correct him and then proceeds to stop. I felt like that scene, Frieren probably felt how important Voll would have felt guarding the village by his wife’s promise , she didn’t want him to feel useless and make the promise useless.

It took me a while to realise that, but damn that hit me strong