What's it like to be friends with the enemy?

Boyfriends and sworn enemies are friends, which is really annoying and crazy for me. My sworn enemy has known me since junior high school. Both of them are excellent and beautiful, and they must have a bright heart. In this case, it is either a friend or an enemy. Unfortunately, we became the latter. Speaking of it, it seems that we have never had a big conflict or obvious hatred, but somehow we have become bitter enemies. It happened that his father broke her mother's head on the day of the college entrance examination. She looked after her mother, but she was late for the exam and didn't enter the examination room. She missed a whole course, so she is not admitted to this university now. People's hearts are all meat, and I sympathize with this situation. And since I'm already with my boyfriend, and she's my sister next door, there's no harm in taking care of her. From then on, we became good friends and cleared up the misunderstanding.