This means you are very sure something is true. You have good reasons to believe it. It is like saying, "There is no doubt about it."
Clause + に相違ないPrimary
Verb [dictionary form] + に相違ない
い-Adjective + に相違ない
な-Adjective + に相違ない
Noun + に相違ない
This means you are very sure something is true. You have good reasons to believe it. It is like saying, "There is no doubt about it."
現場に残された指紋は、犯人のものに相違ない。
The fingerprint left at the scene is, without a doubt, the culprit's.
彼がその重要な情報を漏らしたに相違ない。
There is no doubt that he is the one who leaked that important information.
彼がこの計画を知らなかったに相違ない。そうでなければ、彼の行動は説明がつかない。
There is no doubt that he did not know about this plan. Otherwise, his actions cannot be explained.
調査の結果、事故の原因は人為的ミスに相違ないという結論に至った。
As a result of the investigation, we reached the conclusion that the cause of the accident was undoubtedly human error.
この古代遺跡から発掘された土器は、紀元前のものに相違ない。
The earthenware excavated from these ancient ruins is undoubtedly from before the common era.
This phrase shows you are very sure. You have thought about it carefully. You have looked at all the facts. Anyone else would think the same thing. It is like saying, 'This is just how it is.'
This is like 〜に違いない (ni chigainai). But 〜に相違ない is very formal. You see it in official papers. 〜に違いない is for talking every day. 〜に決まっている (ni kimatteiru) is even stronger. It shows your personal strong belief.
Don't use this when you are talking with friends. It sounds too serious. For example, don't say "That's him, no doubt" to your friend using this phrase.
More formal alternatives(1)
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