Spoilerr
Actually it is said that the one who gives birth to a son and a son that resembles the emperor, will become the empress. Lady Rebecca will give birth to a daughter and die by doing so. As for the rest of the cocubines, one will be chased away, the other will divorce. Later, Paul will give birth to a son that resembles the emperor. She will start hating her son for this. But the emperor will manage to convince her to come back to the capital and stay with him. Since her child is a son, as per the rules, she will become the next empress. Hope this clears things up.
She didn't want to be empress i believe. I read the novel a while ago. And if she a son mean he is an heir to the throne and she will never escaoe the clutch of the emperor and responsibility. She also believed she raped the emperor? So having a son and having a son that resemble him means she really can't lie and get herself out of this. And her son was very beautiful like the emperor. Every time she she sees him, she is reminded of every thing.
This is what I remember. I might get some stuff wrong. Not sure
When they conceived the prince, it was their first night together. I believe both were very drunk and the Emperor does not remember much of that night only the fact that it was the best sex ever in his life(probably because he loved Paul). I think they were drinking after Paul found it the sneke guy was really a snake lol and was a bit saddened by her broken engagement. She believed she forced herself upon the emperor because she think that he would never sleep with a woman like her. Thus she believed she took advantage of him. The emperor even said she was cute and pretty(ded) and Paul didn't even believed a word. I found it hilarious

Is it true that Paul’s kid is the first born of the Emperor? And when will she start love him? And how would he know?