My Queen, Become My Consort

The Crown Prince shouts, "I'm going to give birth!"
"Please. Help me! My queen."
"How dare you to accept the concubine! I will let you experience pregnancy vomiting!"
Finally, Sarah meets her long-standing rival in love,
But there was no bloody scene as imagined.
That woman is gentle and shy like a deer, which makes Sarah unable to help but let go of her guard. She enthusiastically helps hold an ancient version of a blind date!
Sarah doesn't notice that someone has set a trap for her. When she recognized that, Sarah has been sent to the cold palace.
Sarah must revenge! The best way is to give the Crown Prince a big "surprise".
"I want to vomit. Why?"
"Well, there are two reasons." Sarah says.
"First, we changed our souls again. Second, I, no, it's you. You are PREGNANT."