1.
in all sincerity, with one's whole heart
Acting with complete sincerity and dedication; putting one's whole heart into something.
誠心誠意お詫び申し上げます。
I sincerely apologize from the bottom of my heart.
誠心誠意尽くしますので、よろしくお願いします。
I will do my utmost with complete sincerity, so please count on me.
彼は誠心誠意対応してくれた。
He dealt with the matter with complete sincerity.
FOUR-CHARACTER IDIOM (四字熟語):
誠心 (sincere heart) + 誠意 (sincerity)
COMPONENTS:
- 誠: sincerity, truth
- 心: heart, mind
- 意: intention, meaning
LITERAL MEANING:
"With sincere heart and sincere intention" - doubling the concept of sincerity for emphasis.
USAGE PATTERNS:
- 誠心誠意お詫びする (to apologize most sincerely)
- 誠心誠意尽くす (to devote oneself wholeheartedly)
- 誠心誠意対応する (to respond with complete sincerity)
REGISTER:
Formal. Often used in business contexts, apologies, or when emphasizing genuine commitment. Very common in customer service language.