How to say "sincerity" in Japanese

• 誠意せいいCommon
  nounSincerity as good faith or earnestness toward others: the quality you show in an apology, a request, or negotiations to prove you mean what you say. The everyday word for this sense.
  彼かれは無礼ぶれいにも私の誠意せいいを疑うたがった。↗

  He dared to doubt my sincerity.
• 真心まごころJLPT N1approx.Common
  no-adjectiveSincerity as genuine, warm feeling — a true heart directed toward a person. Fits thanks, love, hospitality, or devotion, where the point is that the feeling is real rather than merely proper.
  彼女かのじょは彼かれに真心まごころこめて感謝かんしゃしました。↗

  She thanked him with all her heart.
• 信しんCommon
  nounAs a free-standing word this is seldom what you want for 'sincerity': it names honesty, good faith, and fidelity as abstract virtues, and appears chiefly as an element inside other words and set phrases.
• 忠誠ちゅうせいCommon
  na-adjective, nounReally 'loyalty': allegiance and faithfulness owed to a lord, country, or employer. Its 'sincerity' sense is devotion of that loyal kind, so it is not the word for sincerity in general.
  君きみの忠誠ちゅうせいを当あてにしてもいいかい。↗

  Can I count on your loyalty?
• 誠心せいしんCommon
  nounA formal word for sincerity as a sincere heart; close in meaning to 誠意 but stiffer, so in everyday speech 誠意 is the safer choice.

Choose 誠意 for sincerity as good faith shown to others, 真心 for warm, heartfelt genuineness, 誠心 as a stiffer formal near-equivalent of 誠意, 忠誠 only when loyalty is meant, and 信 almost never on its own.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 誠意せいいsincerity
• 真心まごころsincerity
• 信しんhonesty
• 忠誠ちゅうせいloyalty
• 誠心せいしんsincerity
• 至誠しせいsincerity
• 丹精たんせいworking earnestly
• 徳義とくぎmorals
• 信実しんじつsincerity
• 篤実とくじつsincerity
• 赤心せきしんsincerity
• 実意じついsincerity
• 至心ししんsincerity
• 丹心たんしんsincerity
• 至情しじょうsincerity
• 赤誠せきせいsincerity
• 誠情せいじょうsincerity
• 真率しんそつhonesty
• 実じつsincerity
• 誠まことsincerity
• 情実じょうじつsincerity
• 真実味しんじつみsincerity
• 丹たんsincerity