This one feels like a shoujo manhwa to me...

A commoner became the Queen of Norway thanks to true love.

Before she was the Queen of Norway, Queen Sonja was the daughter of a clothing merchant, dating then-Crown Prince Harald in secret. However, Harald eventually made it clear to his father that he would never get married unless the person by his side was Sonja, and the couple wed on August 29, 1968. Sometimes love can conquer all!