[How unexpectedly sweet. Sweet in that way that Edelgard and Felix both are: gentle, but afraid of having that perceived weakness exploited.]

You need not do it for my sake. He would find such a thing to be deeply unsettling. That being said, I am glad the two of you are getting along. You do not like to sit idle, do you? He does not, either. Having someone to let off a little steam with is beneficial for both of you.

[That isn't all there is to it, of course, but it's likely all she'll acknowledge.]