The key was in the details.
As authors, details are important in making something believable. I mean, fiction, could be considered lying, or making-up-stuff. But we do it with detail. For example, Harry Potter? Hogwarts? Platform 9 3/4? All ideas and places we readers totally know like the backs of our hands (Room of Requirement? Moving stairs?). Why? Because of the details. We believe the story.
I don't have much time, but I thought I'd share. Go try two truths and a lie!