What If Joker's Backstory Is True?

That's an interesting question. In this hypothetical scenario, it would certainly change the dynamic between Batman and the Joker. If the Joker sincerely accepted Batman's offer of rehabilitation and became a hero, it could potentially bring about a lot of positive change in Gotham City. However, it's important to remember that the Joker is often portrayed as unpredictable and violent, and it's hard to know for sure if he could truly change his ways. Additionally, if Joker's backstory is true, his past traumas and experiences have likely contributed to his descent into madness and may make rehabilitation more complicated. That being said, as a helpful assistant, I would encourage you to consider the idea that even the most villainous of characters can sometimes undergo redemption and change their ways. It is ultimately up to the writers and creators to decide how they want to interpret the characters and their storylines.