We say there's 2 sides to a story. Some people say there's 3: his side, her side, and the truth.
I think there's millions. Potentially, there's infinite truths to any truth.
When somebody tells me the truth, and they honestly believe it's the truth, it's their interpretation of an event filtered through their senses, opinions, beliefs and world view.
And that's not even considering other factors: the time of day, the weather, their ability to remember a story accurately, whether they misheard or saw things incorrectly in the first place.
A truth—no matter how much we believe it—is our truth. It's a facsimile of an actual event forwarded through email and narrated back to you through a dodgy telephone line.
Our truths are like our paths through life: unique and no two are quite the same.