In love with the prince

So a girls parents are killed when still young. parents worked for the king and when they died he took the girl to raise her. king has a boy. prince. the two children become very close and are bestfriends. grow up together and it happens that the girl falls in love with the prince in the long run. the boy also has some feelings for her. like each other. become of age and the love is strong. but the girl has no royal blood in her and they cannot marry. king brings in a princess from another country to marry his son to get allies or s. thing. so the drama begins and continues.