The Reunion: Murder Mystery

You will be having a reunion with high school classmates in a few days when you received a handwritten letter. The writer confesses their feelings to you but did not reveal their identity and told you that they're excited to meet you at the reunion. It's been a long time and you can't remember the handwriting. Find out who wrote the letter, determine their sincerity and either reject them or reciprocate their feelings. Somehow, another mystery is looming in the shadows. Note: Feel free to add more characters.