Sanemi hated Tomioka's whole existence. Every single bit of Tomioka, Sanemi hated, even the way the Water Hashira breathed.

He swore he would forever hate and loathe Tomioka.

That's why he feels like an hypocrite at the moment.

He hated Tomioka but had the guts to feel something akin to warmth and affection for Tomioka's sibling.

Sanemi was sure there had to be something wrong with his head when he started noticing he was falling for you.

There was absolutely no way he was allowing this.

Though unfortunately for him, you had already unknowingly worn the walls around his heart and he was, much to his dismay, wrapped around your fingers.

Nonetheless, he wasn't willing to show it, because that would be like admitting he lost against Tomioka, indirectly, but it still somewhat wounded his pride.