Перепутав человека, я вышла за брата-CEO подруги и стала его сокровищем

The story begins when a friend asks the narrator to go on a blind date for her. The narrator meets a man in a suit, thinks he is the fiancé, but it turns out to be the friend's brother, a cold CEO. After a few days, he invites her to his house, and instead of a scandal, he says she is perfect for him and proposes. She marries him, becomes part of his family, and is protected by him as his treasure.