誠せい心しん誠せい意い

adverb, noun, noun which may take the genitive case particle 'no'

in all sincerity; with one's whole heart; whole-hearted devotion

A yojijukugo expressing utmost sincerity and wholehearted effort, often used in formal or earnest contexts.

• 彼かれは誠せい心しん誠せい意い、その問もん題だいに取とり組くんだ。

  He tackled the problem with all his heart.

• 誠せい心しん誠せい意いをもってお詫わび申もうし上あげます。

  I offer my sincerest apologies.