[Leave them unchaperoned, Il!!!! Hiyori is so, so clearly on his best behavior after all. Regardless he gives a smile at that, gracious and welcoming. It's all part of being an idol to know exactly what mask to put on in order to be loved, after all.]

You're welcome, Yona.

[A tilt of his head.]

If we're to be married then I'd best practice how to properly look after you, shouldn't I? I'm sure there's a lot to learn.

[ - because you need so much help.

Also if they're to be married.

But if he says it angelically enough surely it doesn't raise any red flags.]