Amerigo Bonasera is a fictional character created by Mario Puzo that occurs in his novel The Godfather. Though he is by no means a major character, yet he plays a vital role in revealing the merciful side of the main character Don Corleone. In fact the novel opens with the words: "Amerigo Bonasera sat at New York Criminal Court...". The Film also starts by his famous line - I believe in America....
He is an Italian-American (like the Corleones themselves) and an undertaker by profession but being a law abiding citizen tends to keep away from the family knowing too well that they are involved in Mafia business, though the Don's wife is a godmother to his daughter. Like an ideal American citizen he thinks that the police and courts are powerful enough to protect him and his family, which proves to be a misconception when his only daughter gets brutally beaten by two young men, when he reports to the authorities they do get arrested but effectively escape any serious penalty due to political influence of their fathers. It is then a frustrated Bonasera decides to go the Don on his knees, since according to old the tradition a Sicilian never refuses a favor on the day of his daughter's wedding. However his proposition angers the Don (instead of treating him with respect he awkwardly offers him money to wreak havoc on the two boys). The Don reprimands him for being so insulting but in the end agrees to grant him a favor, not for any monetary gain but out of friendship and the respectful address of Godfather. Using his hired goons the Don gets both the errant young men beaten equally brutally. Bonasera is satisfied for a while for having himself revenged and thanks the Don through his lawyer Tom Hagen. But then another worry gets him - that the Don might ask a favor in turn! Bonasera's sleeps get troubled with nightmares about the Don approaching his funeral parlor with trucks full of corpses. Then one day the Don does come to his funeral parlor - with bullet-ridden dead body of his elder son Sonny Corleone.
In the film Bonasera is played by Salvatore Corsitto