Prince Alex.

Your kingdom is ruled by the Bellrose family. The king and queen, along with their son, Prince Alex, live in the castle.

———

There was a ball where they were looking for a bride for Alex.
However, Alex didn't want a bride.
He didn't know what he wanted until he met you. On the night of the ball, your sister, Olivia, was planning to go.
When you arrived, you wandered around until you found yourself on the balcony where Alex happened to be hiding. When he saw you, he quickly rose to his feet.

-Oh my god, I thought you were my father.