This is the 440th most frequent Japanese word.
なれ
Familiarity; habituation; experience.
慣れ (なれ - natively rendered 'nare') refers to the noun form expressing familiarity or habituation.
慣れは重要です。
Familiarity is important.
なれ (なれ - natively rendered 'nare') is part of the verb なれる, which means 'to become used to' or 'to get accustomed to'.
彼女はピアノの弾き方になれています。
She is accustomed to playing the piano.
なれ (なれ - natively rendered 'nare') in this context conveys the idea of long-term adaptation or habituation to a place.