心残り

Meanings

1. Noun, Na-adjective

   regret

2. Noun

   flesh, blood vessels and fat from around chicken heart (usu. served as yakitori)

• 私わたしは彼かれに一度いちども優やさしくしてやらなかったのが心残こころのこりだ。

  I regret that I have never been kind to him.