They gave us like zero background on her outside of the exposition moments about her parents (still very vague) and the bf mess was its own thing.
So I have a feeling that's the twist. Plus we already know they can recognize swans. They seem to think she is his wife. He might have known from the start tbh.
I mean has he shown any interest in any other maids? Not a single one has tried to pretend get a leg up? hmmm

I think he's lying about brainwashing not working on swans. Because how the hell is she falling for this evil fuck. Omg. This is something I can read with my brain turned off