assiduousness       
noun [ U ]  formal uk/əˈsɪdʒ.u.əs.nəs/ us/əˈsɪdʒ.u.əs.nəs/
 (态度)专心致志
the quality of showing great care and attention to detail
  the assiduousness of his care for her 他对她专心致志的关怀 
 He approached his job with a rare assiduousness.  他以一种罕见的专注态度对待工作。 
 See: assiduous
 - More examples
 - It is a sign of her assiduousness that she spent ten years researching and writing the book.
 - Nobody should doubt the energy and assiduousness of the police searching for the murderer of one of their officers.
 - People are often frustrated by the bureaucratic assiduousness of state offices.