[ ... That explains the "we've barely spoken" thing. She doesn't understand, exactly, but she gets the gist of it — or at least why Kasque is concerned. ]

And your affection for this "other" Milla means that you care greatly for her as well, despite a lack of familiarity.

... I will keep this between us. But Lady Kasque, your obvious regard for her feelings shows a great deal of consideration for Lady Milla as an individual, not just the shadow of another. I believe she, too, will realize this; if not now, then given time.