恒こう心しん

noun

steadiness; constancy; unwavering mind

Refers to a steady, unchanging heart or mind; often used in formal or literary contexts to describe perseverance or fidelity of purpose.

• 彼かれはどんな困こん難なんにも負まけず、恒こう心しんを持もって研けん究きゅうを続つづけた。

  He continued his research with unwavering determination, undeterred by any difficulty.