誠心誠意 せいしんせいい Meanings Adverb, Noun, の-adjective in all sincerity; with one's whole heart; whole-hearted devotion Kanji 誠 sincere. Read as セイ. 心 heart. Read as シン. 意 mind. Read as イ. Word lists Yojijukugo (四字熟語) Jinuma: Japanese Dictionary · Word lists