If I'm not wrong, nobody knows it except the royal family (and the teachers). Because king was afraid nobles could think that she had mental illness.
nearly everyone in that room knew about it then, except one or two additional characters.
No, to my understanding in the royal family only the king knows. The Rest only heard that she recovered from the poisoning. They were never told about her memory loss.
the only one who knew that she had an amnesia is the emperor, the duke, the gray haired old dude, the doctor, and her personal maid ig.
we know she's not the real princess, but everyone knows marianne lost her memory. in which point we were informed they've came back perfectly? it wasn't about her selfishness or anything.