I'm Looking for an Extra Chapter in an Ancient Romance That's so Cruel That You Fall in Love but Can't Stay Together.

A man and a woman grew up together. The man is a son of a noble family, and the woman, a princess of a country, needs to be the heroine's maid. The man's parents kill the man's father by mistake, and they forbid him from dating the woman. After a few years, the daughter's brother ascends the throne, but the woman cannot be together because of the differences between them and the man. They can only stay together silently and eventually die.