How we cite our quotes: All quotations are from Batman.
Quote #1
THUG 2: What are you?
BATMAN: I'm Batman.
Notice the thug says what are you, not who are you? Batman is so mysterious at this point, that people aren't even sure if he is human.
Quote #2
VICKI: Could you tell me which of these guys is Bruce Wayne?
BRUCE: I'm not sure.
Bruce's response is a flirty joke, playing around with Vicki Vale so he can later surprise her that he is, in fact, Bruce Wayne. But if you read into this even more (which we love to do) you can see a little bit of Bruce's existential crisis coming out. If he isn't sure whether to be Bruce or Batman, maybe he isn't Bruce Wayne anymore.
Quote #3
KNOX: The guy's a stiff. He's a rich stiff, but you could do much better.
Knox wants to win Vicki over by putting down Bruce. It doesn't work. Later in the movie, Knox, with a baseball bat, fights off a bunch of bad guys. We're not sure if he does it out of the goodness of his heart, to impress Vicki, or a little of both, but it shows a bit of character evolution in his identity. He goes from a self-serving journalist hack, to a self-serving journalist hack who's willing to risk his life to fight crime. He and Bruce have something in common.