N2 Grammar ③　に違いない

に違いない vs に決まっている vs はずだ — degrees of certainty

'No contact since morning — she must have already left.' Learn to express certainty precisely, from logical deduction to gut feeling.

What you'll learn

• に違いない: evidence-based certainty (formal, written)
• に決まっている: subjective, gut-feeling certainty (colloquial)
• はずだ: expectation based on reason (medium certainty)
• かもしれない: uncertain possibility (low certainty)

JLPT N2 Japanese self-study — interactive practice, instant feedback, completely free.