誠心誠意 [ㄔㄥˊ ㄒㄧㄣ ㄔㄥˊ ㄧˋ; cheng2 xin1 cheng2 yi4]
  earnestly and sincerely (idiom); with all sincerity
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  誠心誠意
  せいしんせいい
  adverb (fukushi)
  noun (common) (futsuumeishi)
  nouns which may take the genitive case particle `no'
  in all sincerity
  with one's whole heart
  whole-hearted devotion
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