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JLPT N2Hearsay & Conjecture

に相違ない— Beyond All Doubt

Expresses the speaker's strong conviction that something must certainly be the case, based on reasoning or evidence. It is a formal, written equivalent of に違いない. Because it is stiff, it appears mainly in documents, legal or literary writing, and formal statements rather than conversation.

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Pro lessonUNIT 48 · HEARSAY & CONJECTURE

Structure · 形

[Noun / な-adj stem / Plain form] + に相違ない

Examples · 例文

  • この筆跡から見て、犯人は彼に相違ない。

    Kono hisseki kara mite, hannin wa kare ni soui nai.

    Judging from this handwriting, the culprit must certainly be him.

    Noun 彼 + に相違ない expresses firm conviction based on evidence

  • この事故は彼の不注意が原因に相違ない。

    Kono jiko wa kare no fuchuui ga gen'in ni soui nai.

    There is no doubt that his carelessness was the cause of this accident.

    Noun 原因 + に相違ない asserts firm conviction about the cause

  • 彼女が優秀な人物であることは事実に相違ない。

    Kanojo ga yuushuu na jinbutsu de aru koto wa jijitsu ni soui nai.

    That she is an excellent person is doubtless a fact.

    Noun 事実 + に相違ない asserts certainty in a formal register

Usage notes · 注意

  • Register: very formal and written; use に違いない in normal conversation.
  • Expresses subjective certainty, not objective proof — 'I am sure that…'.
  • Frequently found in legal, journalistic, and literary texts.

Commonly confused with

The JLPT rarely asks whether you recognise a pattern — it asks which of several similar patterns fits. These are the ones に相違ない is tested against.

vsに違いない

に違いない carries the same 'must be' certainty but is used in everyday speech; に相違ない is its stiff, formal-writing counterpart.

vsはずだ

はずだ expresses logical expectation ('it should be, based on facts'), while に相違ない expresses the speaker's strong personal conviction.

More hearsay & conjecture

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