Well, it could be about a situation where someone was wrongly thought to be a hitman. Maybe there was some sort of misidentification or false rumors that made people believe a person was involved in hitman - like activities when in reality they weren't.
Well, in some 'fake hitman true story' scenarios, the person might have had some strange encounters that were misinterpreted. For instance, he might have met some shady - looking people by chance, and these meetings were blown out of proportion and made to seem like he was involved in the hitman business. Another possibility is that there were some forged documents or false testimonies that led to the false belief that he was a hitman.
Definitely not. The Hitman is purely fictional. It was made up to provide an engaging and thrilling story rather than being drawn from real-life happenings.