gentleness vs solicitude

gentleness

noun
  • The state of being gentle. 

solicitude

noun
  • Special or pronounced concern or attention. 

  • The state of being solicitous; uneasiness of mind occasioned by fear of evil or desire for good; anxiety. 

  • A cause of anxiety or concern. 

How often have the words gentleness and solicitude occurred in a corpus of books? (source: Google Ngram Viewer )