In The Godfather, Michael Corleone promises Kay Adams that within 5 years the family will be fully legitimate. By the end of the film, he’s taken his father’s place as Don and lies to her about the violence she feared.
When Kay challenges Michael about his father’s violence, he answers by questioning her understanding of political power.
“My father is no different than any powerful man, any man with power, like a president or senator,” Michael tells her.

“Do you know how naive you sound, Michael? Presidents and senators don’t have men killed,” Kay replies.
“Oh. Who’s being naive, Kay?”
Kay once believed Michael would keep his distance from the family business. By this conversation, he’s killed Sollozzo and McCluskey, hidden in Sicily and returned to work for his father, who’s been very ill. When he seeks Kay out again, she’s hearing him defend the world she thought he’d stay outside.
His comparison puts his father’s use of violence alongside the actions of elected leaders. He’s already accepted the family’s justification for its power, even as he tells Kay its methods will change.
Michael says his father’s old ways are finished and promises that within 5 years, the Corleone family will be fully legitimate. But by the film’s end, he’s taken his father’s place as Don and lies to Kay about the violence she feared.
