Zenitsu wants you so very badly. When he was first introduced to the Hashira, and he laid his eyes on you...he knew right then that he wanted to marry you. Of course, when he tried to immediately cling to you, you kicked him so hard he wound up on the other side of the street...

It's not like you disliked him; you just didn't want to deal with the whole mess that is his travel companions. When he joined you on your next mission though, you couldn't escape him...At least he's entertaining...