に違いないni chigai nai“must be; no doubt”

に違いない means must be; no doubt. It is a JLPT N3 grammar pattern used to state a strong conclusion based on evidence.

This grammar point often appears in neutral Japanese. If you want to state a strong conclusion based on evidence, に違いない is a useful pattern to learn.

What does に違いない mean?

Use に違いない when you want to state a strong conclusion based on evidence.

Natural translations include:

• must be; no doubt
• must be
• must be / no doubt

How to form に違いない

Plain form + に違いない / Noun + に違いない

Examples of the pattern:

• 本当 に違いない
• 知っているに違いない
• 大変だったに違いない

When is に違いない used?

Use に違いない in situations like:

• explaining context clearly
• answering JLPT reading questions
• making natural Japanese sentences

Tone and register:

• neutral
• Common in JLPT reading, grammar questions, and natural Japanese sentences

に違いない example sentences

• 彼はもう家に着いたに違いない。 — He must have arrived home already.
• この足跡は犬に違いない。 — These footprints must be from a dog.
• 彼女は試験のために一生懸命勉強したに違いない。 — She must have studied hard for the exam.
• あの店は人気があるに違いない。 — That shop must be popular.
• こんなに静かなら、みんな帰ったに違いない。 — If it is this quiet, everyone must have gone home.

Nuance of に違いない

The key nuance is a practical way to express “must be; no doubt” with the right level of emphasis.

This matters because に違いない does more than translate one English phrase. It tells the reader how the speaker is framing the situation, whether as emphasis, contrast, obligation, approximation, or evidence.

For example:

• In context, it sounds natural when the surrounding sentence supports the nuance.
• Compared with はずだ, it has a different focus and level of formality.

に違いない vs はずだ

Both に違いない and はずだ can appear in related situations, but they are different.

に違いない:

• means must be; no doubt
• fits the specific N3 pattern and nuance explained above

はずだ:

• はずだ is expectation based on logic; に違いない is stronger certainty

Quick contrast examples:

• Target: 彼はもう家に着いたに違いない。 — He must have arrived home already.
• Compare: Try replacing it with はずだ and check whether the nuance still matches.

Common mistakes with に違いない

Watch out for these mistakes:

• Using に違いない with the wrong form
• Confusing に違いない with はずだ

Is に違いない on the JLPT?

Yes. に違いない is commonly taught as JLPT N3 grammar.

That means learners should be able to:

• recognize it in reading
• understand its nuance in context
• use it in simple original sentences

Practice questions for に違いない

• Write one sentence using に違いない.
• Contrast に違いない with はずだ.
• Make a JLPT-style sentence with a clear context.

Learning path for に違いない

To learn に違いない efficiently, review basic particles like について and に, then focus on the relationship each formal marker creates.

1. First, make sure you can form に違いない without looking at the pattern chart.
2. Next, compare it with はずだ, に対して（にたいして）.
3. Finally, write reading-style sentences about society, research, policy, opinions, and reports; then check whether replacing に違いない with にとって changes the meaning.

Related grammar to review next

• はずだ — should be; expected to be.
• に対して（にたいして） — toward; against; in contrast with.
• にとって — for; from the viewpoint of.
• について — about; regarding.

Learn に違いない with Hane

If you want to review に違いない together with the related patterns above, Hane helps you connect grammar, kanji, and vocabulary in short, focused sessions.

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