Originally Posted by Ecuanime
As much as I would like to say Rachel, being that he grew up with her and seen her as a way to be a normal person, but then to be left devastated after her death in TDKR. The ideal relationship looks good on paper, but did not work for me on screen in BB and TKR. In BB, we never really know exactly why Bruce is in love with Rachel. We know that she was part of his childhood and also she convinces him that killing won't solve his problems. But there's no intimacy in the film between the two.
In TKR, we have a new actress playing the role, in which she did well. But again, no real intimacy. We don't see what Bruce sees in her, my thoughts would be she, other than Alfred, is only person that knows him from childhood, when his life was normal, innocent and not vengeful. But as for a deep connection between her and Bruce, nothing. On top of that, the audience really don't care for her. What really illustrates this is the fact that in the film, she gets blown away right in front of us--which comes as a complete shock and defies superhero films because the damsel usually doesn't die--but her death soon becomes an afterthought as we are absorbed into what Joker does next and the emergence of Two Face. We really don't know--and forget--how much her death affected Bruce until TDKR.
Today I think the impression that doesn't worked, manly in TDK, was on purpose. First, because Rachel already moved on, and because I think Bruce was more "in love" of what Rachel represented than her as a human being. Was almost an obsession. He saw she was with Harvey, maybe even living with him and was like nothing to him.