@Hollow7F Um, no? He want to die defeating Muzan and reborn in a world without demons, after that he'll say that he loves her.
And hey, she's a woman. Women have a higher pulse, so the poison will spread quicker than in other Hashira's bodies. And she got poisoned about 4 times, moreover she was cut in neck and chest, so the poison had the best openings.
@ghostkun wtf. All of pillars had a backstory, so he too. It's normal we didn't know much about him before.