[Lucina lets out a breath of air she didn't realize she was holding, and deflates. Quite a bit, at hearing that sort of information.]

What I'm about to tell you goes hand in hand with the comment I made earlier, you see. When I was there, so were Severa and Nah, but at some point, Severa disappeared, only to later come back from a place called Nohr, and apparently had a child there. And if what you tell me is true, I thought it plausible that my brother may have... You know. [She doesn't want to think about Inigo having sex with some random tavern worker, thank you.]

Especially if Severa had.