にちがいない Japanese Grammar Lesson
Grammar Type: Phrase
Essential Meaning: There is no doubt that
Construction:
- (Verb / い-Adjective) informal + にちがいない
- E.g. 話すにちがいない [There’s no doubt that X talked / There’s no doubt that X will talk]
- E.g. 高いにちがいない [There’s no doubt that X is expensive]
- (な-Adjective Stem / Noun) + [X / だった] + にちがいない
- E.g. 静かにちがいない [There’s no doubt that X is quiet]
- E.g. 先生だったにちがいない [There’s no doubt that X was a teacher]
Notes:
- にちがいない conveys a strong sense of probability / confidence in some proposition. In other words, the speaker believes that the proposition that precedes にちがいない is undoubtedly true or correct.
- E.g. あの人は日本人にちがいない。[That person is undoubtedly Japanese.]
- In written Japanese, the proposition that precedes にちがいない may be nominalized with の to convey extra confidence in the speaker’s assertion.
- E.g. 日本の経済はよくなったのにちがいない。[There’s no doubt about the fact the Japan’s economy has greatly improved.]
- E.g. 家を買うのはあまり難しくないのにちがいない。[There’s no doubt that buying a house is not so difficult.]
- In terms of confidence: にちがいない > だろう > かもしれない. In other words, にちがいない conveys the most confidence, and かもしれない conveys a low level of confidence.
- E.g. あの人は日本人にちがいない。[That person is undoubtedly Japanese.]
- E.g. あの人は日本人だろう。[I’m pretty sure that person is Japanese.]
- E.g. あの人は日本人かもしれない。[That person is perhaps Japanese.]
- There are cases in which にちがいない can be interchanged with はずだ. The difference between the two is that はずだ expresses an expectation based on reliable facts or evidence, while にちがいない is not necessarily evidence-based.
- E.g. そのアパートはきれいなはずだ。[I expect that apartment is clean.] The implication here is that the speaker’s expectation is based on some kind of evidence. Perhaps the apartment owner is a very tidy person, so it’s reasonable to expect that their apartment would be clean.
- E.g. そのアパートはきれいにちがいない。[That apartment is undoubtedly clean.] The speaker is very confident in his or her assertion that the apartment is clean, but this confidence may or may not be justified.
Example Sentences:
下田さんは今日のことを忘れたにちがいない。[Shimoda-san undoubtedly forgot about today’s plans.]
あの先生の試験は難しいにちがいない。[That teacher’s tests are undoubtedly difficult.]
ベイリーさんはテニスが上手にちがいない。[There is no doubt that Ms. Bailey is good at tennis.]
二人は今頃ハワイで楽しく泳いでいるに違いない。[Right now those two are undoubtedly having fun swimming in Hawaii.]
一人で外国へ行くのは大変にちがいない。[There is no doubt that going abroad on one’s own is difficult.]
山口さんは頭がいいにちがいない。[Mr. Yamaguchi is undoubtedly smart.]
あれはトンプソンさんにちがいない。[There is no doubt that is Mr. Thompson.]
WILD Examples:
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