He didn't mean to fall in love with her. He knew he shouldn't. He wasn't the Robin she was supposed to be with. He would never be Dick Grayson and he would never be good enough for her, but he could try. He would try his best, he might never be someone Jim Gordon would slap on the back and offer a cigar to but he could try to be better for her. She might never understand why he sometimes chooses to kill, he may never understand how she could forgive Bruce for not killing the Joker after what he did to them, but she understood more than most.
She could understand his pain though, understand why both of them flinched at the manic laughter. He could understand why her heart sped up at the sight of a camera and she could understand his face paling at the side of the crowbar. They could understand each other when it came to him. When it came to the Joker, they had no one but each other. Barbara would wake up in the night sometimes and find Jason already awake and both wouldn't need to say a thing, the nightmares came with their scars. Jason would often find Barbara staring off into the distance and rubbing her legs absentmindedly and Barbara would often watch as Jason became twitchy whenever he was around a countdown.
No one could understand at first, how the two could fit. Jason remembers the stares as Barbara brought him into a Bat family dinner. He remembers the disapproval but he also remembers Barbara's sweet smile, the way her hand fit in his and how her lips felt against his. Batman himself couldn't have stopped them, though Jason is pretty sure he may have tried to talk Barbara out it. Barbara was a glimpse of hope for him and maybe she could save him, like he never could himself. All Jason knew was that he was in love with Barbara Gordon and he was pretty sure she loved him too.