(せいしんせいい)

せいしんせいい
noun (four-character idiom)
in all sincerity; wholeheartedly
1. in all sincerity, with one's whole heart
Acting with complete sincerity and dedication; putting one's whole heart into something.
誠心誠意(せいしんせいい)()(もう)()げます。
I sincerely apologize from the bottom of my heart.
誠心誠意(せいしんせいい)()くしますので、よろしくお(ねが)いします。
I will do my utmost with complete sincerity, so please count on me.
(かれ)誠心誠意(せいしんせいい)対応(たいおう)してくれた。
He dealt with the matter with complete sincerity.

FOUR-CHARACTER IDIOM (四字熟語(よじじゅくご)):
誠心(せいしん) (sincere heart) + 誠意(せいい) (sincerity)

COMPONENTS:

  • (せい): sincerity, truth
  • (しん): heart, mind
  • (): intention, meaning

LITERAL MEANING:
"With sincere heart and sincere intention" - doubling the concept of sincerity for emphasis.

USAGE PATTERNS:

  • 誠心誠意(せいしんせいい)()びする (to apologize most sincerely)
  • 誠心誠意(せいしんせいい)()くす (to devote oneself wholeheartedly)
  • 誠心誠意(せいしんせいい)対応(たいおう)する (to respond with complete sincerity)

REGISTER:
Formal. Often used in business contexts, apologies, or when emphasizing genuine commitment. Very common in customer service language.