If writing isn’t truthful, readers can tell. That doesn’t mean it’s all pulled from real life. Writing is also about creating new realities. You have to make things up sometimes to get at the truth. It’s a contradiction that non-writers can have a hard time wrapping their heads around.
Here’s what Jamie Quatro told The Paris Review:
Fiction begins with small, lower-case truths, then translates them into a larger lie that ultimately reveals the largest truths. “None of it happened and all of it’s true,” said Ann Patchett’s mother.
And remember what Tim O’Brien wrote in “How to Tell a True War Story“:
Absolute occurrence is irrelevant. A thing may happen and be a total lie; another thing may not happen and be truer than the truth.