When the 格助詞（かくじょし）
に is combined with the noun 違（ちが）い ‘difference’, and the
い-Adjective ない, an expression similar to ‘there is no doubt that (A)’, or ‘I’m sure that (A)’ is created.
に違（ちが）いない may be used with any verbs,
い-Adjectives,
な-Adjectives or nouns in their plain form.
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彼（かれ）らは、先生（せんせい）がいなくなったらふざけるに違（ちが）いない。
There is no doubt that they will muck around once the teacher has gone.
あなたが美味（おい）しいというなら、美味（おい）しいに違（ちが）いない。
If you say that it is good, I have no doubt that it is.
タナカ君（くん）は全然（ぜんぜん）料理（りょうり）を食（た）べてない。この料理（りょうり）が嫌（きら）いに違（ちが）いない。
Takana-kun is not eating his food at all. There is no doubt that he does not like it.
今（いま）のピンポンは近所（きんじょ）の子供（こども）のいたずらに違（ちが）いない。
There’s no doubt that the doorbell I just heard must have been a prank by the neighbor's kid.
As
に is marking the preceding word in this expression as an existing location (or state), 違（ちが）いない is stating that no ‘variance’ exists within that state. This means that the literal translation of
に違（ちが）いない is close to ‘there is no discrepancy in (A)’.
It should be noted that 違（ちが）いない is a combination of a noun and an い-Adjective, and not the negative form of the う - Verb 違（ちが）う, which would be 違（ちが）わない. 違（ちが）いない translates as ‘there is no difference’, while 違（ちが）わない would translate as ‘it is not different’.