〜に違いない

Must be; Surely

1. Overview

「〜に違いない」is a grammatical structure used to express strong belief or certainty regarding a particular situation or fact. It indicates that the speaker is quite confident about something being true.

2. Structure

• Grammar Structure:

  • Verb (plain form) + に違いない
  • Adjective (plain form) + に違いない
  • Noun + に違いない

• Explanation:

  • 「〜に違いない」means "it must be" or "there's no doubt that," showing high confidence in the situation or fact being described.

3. Usage Explanation

• Inference: It is commonly used to express the speaker's subjective judgment or inference about something likely being true.

• Strong Belief: This expression is often used in formal contexts or written language, emphasizing the speaker's certainty.

• English Translation: This structure is typically translated as “must be” or “surely.”

4. Example Sentences

1. 彼はもう帰ったに違いない。
   He must have already gone home.

2. この料理はおいしいに違いない。
   This dish must be delicious.

3. 彼女は忙しいに違いない。
   She must be busy.

5. Key Points to Note

• Tone: Using 「〜に違いない」conveys a strong tone, indicating the speaker's confidence.

• Based on Facts: This expression typically requires some facts or situations as a basis for the inference being made.

6. Similar Grammar

• 〜に決まっている: Also used to express inference or certainty but with a stronger tone, emphasizing that there are no other possibilities.
  • Example: 彼は遅れるに決まっている。
    (He is definitely going to be late.)

7. Alternative Grammar

• 〜はずだ: Used to express a reasonable inference, with a relatively weaker tone.
  • Example: 彼は来るはずだ。
    (He should be coming.)

8. Summary

「〜に違いない」is used to express strong belief or inference about a situation, emphasizing the speaker's certainty. It is applicable in both daily conversation and written language, typically used in formal contexts.