She doesnt need to know her origins, her loyalty lies with Sylvester and if rozemyne said she wanted to be aub than riyhardha wouldve reported that, and if sylvester said to get rid of her than she wouldve.
Considering she was appointed to and is loyal to sylvester first and foremost, and when ever she received her assignment she was informed from both that they didnt intend for her to be aub i disagree. She'd probably report it first but if sylvester said to kill rozemyne than Rihyarhda would.
Regrettably she doesnt learn this until much later when Wilfrieds points it out, she learned noble common sense from someone just as abnormal as she is and so she gets to be doubly abnormal.