Così fan tutteCo‧sì fan tut‧te /ˌkəʊsi fæn ˈtʊti $ kəʊˌsiː fɑːn ˈtʊteɪ/ 
a humorous opera by mozart in which two men play a trick on the two sisters they love in order to test whether the women really love, them and will be faithful to them
a humorous opera by mozart in which two men play a trick on the two sisters they love in order to test whether the women really love, them and will be faithful to them