#honestly Batman stories are the best when they're about constructed personas and identity crises

[psalmsofpsychosis]

What Evil Means to Us, by C. Fred Alford

I always wonder what woud happen if bruce finally got what he wanted and got joker all figured out. Would he get bored of him? I think thats something that joker himself is scared of

It's definitely something Joker fears, yes. In Batman: Death of the Family, he basically jumps off a cliff rather than hear Bruce utter his name or his history, so panicked that he doesn't even consider that Bruce could be bluffing. As to Bruce figuring Joker out... hah. Arguably, he already has.

Bruce has always been obsessed with understanding Joker, and especially during his first decade as Batman. At the basis of it lies both a need for control and the hope that Joker could be rehabilitated, because if Bruce understands Joker, then maybe he could predict him and prevent his crime sprees. Perhaps Bruce could help Joker, have the leverage of Joker's humanity to use in order to reach him.

Detective Comics #1027 -- Many Happy Returns

It's an essential component of their dynamic: Bruce desperately asking "why?" and Joker laughing in his face, symbolizing both Batman's need for constructing meaning and Bruce's need for connection and understanding. Something that Joker eternally resists.

Batman (2016) #67 -- All The Way Down

But the paradox is that, at the same time, Bruce doesn't entirely want to figure Joker out. This is partly covered by a bigger pattern of behavior for Bruce that I talked about before-- the fact that, despite verbally supporting the rehabilitation of his Rogues, Bruce tends to be mean-spirited, distrustful and paranoid when it actually happens. In many ways he thinks of the Rogues as his; they're all in the dark, they're all wrestling with various kinds of demons, and Bruce includes himself in it. This is most apparent in Arkham Asylum: A Serious House on a Serious Earth, in which Bruce's biggest fear is the fact Arkham would feel like home. So... if the Rogues truly rehabilitated, what then? Where would that leave him? Bruce has a crippling fear of abandonment as a consequence of losing his parents, and it extends to this.

It's true for Joker more than for anyone else, I suppose. Bruce refuses to let Joker die, even in bonkers circumstances in which his code would allow for it. He also has apparently known all along what he needs to do in order to... undo Joker. If Death of the Family established anything, it's that Bruce never needed to kill Joker in order to get him to stop. The end shows that Bruce knows Joker very well, and thus he knows that the thing Joker fears most is the ghost of his own past. All he needed to do was hint that he had uncovered Joker's history, and Joker basically committed suicide. Yet Bruce hasn't used this before, and he hasn't used it against Joker since.

But I absolutely need to mention the controversial and dubiously-canonical Batman: The Three Jokers (intended to be a spiritual successor to Batman: The Killing Joke) that explores the idea that Joker might've been separate people over time (but not really). This comic is disliked for very valid reasons, but it does something very interesting, at least in the realm of the hypothetical: it shows that Bruce has known who Joker was and where his family is all along. Coupled with the fact that this comic specifically connects The Comedian to New 52 and Endgame... it implies that at least in this story, Bruce wasn't bluffing when he said he knew Joker's real identity in Death of the Family.

But he doesn't use it. Not in Endgame, not in The Three Jokers. I talked about this story more extensively here, but the reasoning that he does it to protect Joker's hidden family is very weak, because Bruce could just omit the fact Jeannie and her child survived. If he's worried about the paper trail, it's ridiculous to assert that Batman doesn't have the resources to fake their death certificates or bury the clues. Hell, the press wouldn't need to find out, he could only tell the truth to Joker and watch him unravel as a result. But he doesn't! In his own words...

Batman: The Three Jokers #3

So... this comic basically goes to show that Bruce wouldn't get bored if he figured out the "mystery" of Joker. Rather that he'd just keep it a secret, and maintain the status quo (even though it's painfully selfish and destructive of him to do so). And even if you see The Three Jokers as out of main continuity, Death of the Family remains as a testament to the fact Bruce knows Joker. He knows what might get Joker to stop, but he's only ever threatened it and never resorted to it since, despite seeing proof of it working.

At the end of the day, Bruce getting bored with Joker is unlikely. It would be a real possibility if their dynamic was based only on Bruce's curiosity and obsession regarding Joker, but it isn't. That's simply a component of it, one of the pillars. Bruce needs Joker in other ways-- bigger ways, that overshadow knowing Joker's name. Joker needs to remain an equal who can oppose Batman... and thus, he keeps coming back, whether he likes it or not. Bruce drags him with him; and I wish I was being metaphorical, but this is literally what Bruce did in Going Sane and the nebulous time between Batman (2011) #48 and Dark Days: The Casting.

The tragedy, though, is that Joker would never trust Batman to still be there outside of the murder and the mayhem he thinks Batman needs. The thought of Bruce caring about him outside of his Joker persona is an impossibility... because Joker utterly hates who he used to be, and sees no value in himself (or anything, for that matter). He can't comprehend Bruce valuing him as a human being, worth knowing or saving.