Verb/Adj (plain form) / Noun (である) + に相違ない

[Without a doubt / Must be / Certainly]

Connection: Verb (plain form) / い-Adj / な-Adj (である) / Noun (である) + に相違ない

Usage: A very formal and literary expression meaning "there is no doubt that." Equivalent to に違いない but much more formal. Used primarily in written language, legal documents, and formal speeches.

Similar expressions:

• に違いない = must be (standard)
• に相違ない = must be (very formal/literary)
• に決まっている = definitely (casual)

Examples:

この作品は彼の手によるものに相違ない。(This work is undoubtedly by his hand.)

犯人はこの建物から逃げたに相違ない。(The criminal must have escaped from this building.)

これほどの成果は、チーム全員の努力の賜物に相違ない。(Such achievements are undoubtedly the fruit of the entire team's efforts.)