When you tell the story of your life to your grandchildren you are entering into an agreement with them. You agree to tell them the truth and they agree to believe you. However, it is next to impossible to be completely truthful in the telling of your life story. Your memory is not going to be perfect. Sometimes, you want to tell more than the truth; you want to tell a higher truth. Telling the absolute truth is very, very difficult.
Here are four solutions.
First, start by telling your grandchildren that they can trust you to tell the most truthful story you can. Explain to them that you can be trusted to tell the most truthful version you can remember. Be sure to start your letter with this information. Don’t leave it for the end. Be honest from the start. Whatever your standards are, disclose them at the beginning of your work.
Second, you can explain your writing style in advance. That you write with a humorous slant, and they should know that when you do, you are just trying to be funny. That you are going to intentionally leave out things you think would hurt someone unnecessarily or cause family division.
Third, do not intentionally add things to your story that did not happen in real life. You can express how you felt in detail, but falsifying reality breaks the bond between you and your reader. Be transparent.
Fourth, tell them you are injecting a story, and it is totally fictional. Then write a story that you can embellish as much as you want. Sometimes in a story that is totally fictional you can tell a higher truth.