Certain; without doubt. An emphatic expression of certainty.
あの人が犯人で間違いない。
There's no doubt that that person is the culprit.
彼の説明は筋が通っていて、間違いないと思う。
His explanation makes sense; I think it's definitely correct.
この店のラーメンは間違いないよ。
This shop's ramen is guaranteed (always good).
Reliable; dependable. Used to praise someone's or something's trustworthiness or quality.
このエンジニアなら間違いない。
You can't go wrong with this engineer.
ブランドの製品は間違いない品質だ。
Brand-name products have dependable quality.