Hi! Can I ask for a help to find this story? But unfortunately I don't remember the fl but...

Hi! Can I ask for a help to find this story? But unfortunately I don't remember the fl but I remember her brother lol the brother has blonde (golden) long hair he wears glasses I think the fl and the brother is not siblings by blood the brother was adopted I think?? And also I remember the brother and a knight has a close relationship lol