Characters
I wonder why your story never wavers from exactly the same words. It suggests either that you have an extraordinary memory…or you’re telling the plain, unvarnished truth.
— Howard ‧ The Letter

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker notices that a story stays word for word the same and offers two explanations: exceptional memory or truth. That pairing makes consistency the object of scrutiny. The statement leaves its alternatives open, asking what an unchanging account reveals about the person telling it.
Context reviewed