Batman: Europa has some curious moments and here’s one of them.
Batman’s reaction, when he finds out that Joker let Nina die although he could have saved her, is rather puzzling to me. The Joker would have killed the girl anyway, probably. But this is not really the case here. The thing is, Batman acts as if he didn’t rememeber that Joker “let” her die, because he was busy saving him (Batman: Europa #3). He chose to help Batman rather than do anything to save Nina. And in the last issue Batman seems to have no memory of it.
The main problem with Batman is probably that he is so focused on Joker’s murderous side that it prevents him from seeing anything else. He simply doesn’t want to acknowlegde any Joker’s attempts at cheering him up, amusing him or flirting with him. Generally, Batman seems unaware of the Joker’s side that isn’t deadly or menacing but humoruos and flirtatious.
He is actually surprised by the Joker’s language abilities or his familiarity with European cities. It shows how little he really knows about the Joker.
Batman: Europa is already famous for its countless references to the possible Batman/Joker intimate relationship. But the whole thing rather highlights why their relationship is so problematic. There is Joker who, as always, confuses violence with love. And Batman who is apparently incapable of noticing these characteristics of the Joker’s personality and behaviour which don’t fit the scheme of utter evilness.