Love's Torment

The heroine is a 'toy' bought by the hero's father to accompany him as he grows up. Unfortunately, she has already fallen in love with the hero. However, when he becomes an adult, he wants to get married for business, and the heroine begins to commit suicide and self-mutilation. Unexpectedly, her brother is already older than her. I fell in love with myself earlier, but I couldn't do anything...