正月になったらみんなに腹いっぱい食べさせてやりたいし…
"When New Year comes, I want to let everyone eat their fill…"
Early in episode 1, before the tragedy. Tanjiro heads down the snowy mountain to sell charcoal despite his mother's worry — he wants to provide for his family. The warmth here makes what follows hit harder.
よくも俺に、虎杖を！弟を、殺させようとしたな！！
"How dare you try to make me kill Itadori — my brother!"
Choso's turning point in Shibuya. After fighting Yuji, he becomes convinced Yuji is his younger brother — and realizes the enemy manipulated him into nearly killing his own family. The rage is personal.
息の根止めさせていただいてもよろしいでしょうか？
"May I be allowed to end your life?"
Yor's assassin side — the Thorn Princess. The comedy is the contrast: she asks permission to kill with humble, ultra-polite keigo. Gentle and awkward in daily life, terrifying on the job.