this plot is really common but maybe this one? https://www.mangago.me/read-manga/another_typical_fantasy_romance/
No sadly its not
There are a lot of stories on this plot. Any other idea? On hair colour??
I think the main boy has black hair and the Prince was blonde and when she went to the Dukes house the step mother wanted the female lead gone
girl just described all historical-royalty manhwa
Well in this one her parents love her and are still alive
Step mother of ML??
Yeah the male lead
Sadly it is not it
Hope you find it soon. Was it completed?
Yes it's completed
It's a historical straight manwa the female lead breaks up with her fiancé and gets engaged with a northern Duke. At first the Duke didn't like her at first but started liking her