optimistic vs reassuring

optimistic

adj
  • Expecting the best in all possible ways. 

  • Allowing other processes to perform transactions on the same data at the same time, and checking for conflicts only when changes need to be written back. 

reassuring

adj
  • That reassures; causing comfort or confidence. 

noun
  • reassurance 

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