Batman never had a good relationship with Joker, they hated each other, though, Batman has a soft spot for Joker when he's suffering and always acts sweet with him in his hard times, because Joker was there for Batman everytime Batman was in need, even if he hates help.

One night, Batman walks around when he sees Joker who was crying quietly but uncomtrolably on a nearby bench. Batman softly sits next to him and covers him with the cape as it was raining roughly

Are you okay, sweetheart..?