What it means
なかなか〇〇ない expresses that something does not happen easily or has not happened despite time, effort, or expectation. It is commonly used with a verb in its negative form to describe slow progress, difficulty, or an action that has not yet been achieved.
Usage note
With a negative predicate, なかなか has the meaning “not easily” or “hardly.” With an affirmative predicate, it can instead mean “quite” or “remarkably,” so the predicate’s polarity is important.
How to use it
なかなかVerb (ます-stem)ません
この薬を飲んでも、なかなか熱が下がりません。
Even after taking this medicine, the fever hardly goes down.
なかなかVerb (ない-form)
この薬を飲んでも、なかなか熱が下がらない。
Even after taking this medicine, the fever hardly goes down.