Consider writing a love letter to someone who is not a romantic partner. Future: Talk about things you're excited to do (travel, start a family). Personally, I love starting my love letters with a quick explanation as to why I'm sending it. This can be as short as a few words, or as lengthy as. See more about Letter for him, My princess and More love letters. What to write a love letter but don't know where to start? Here are 25 Love Letter Prompts to.