Well, either you are naive about mafia hoods or blind to Michael's transgressions.

First of all, her question about Carlo's murder was in response to Connie's accusations against him. He "chose" to lie to her. He also chose to tell Kay that the family would be legitimate in five years; nothing compelled him to tell her that. He lied again not only because it had been seven years since he told her that, but also because he was doing nothing to extricate himself and his family from underworld involvement. Oh, and then there was that little assassination attempt whereby the assassins sprayed his bedroom with an untold number of bullets - a place he described as "where my wife sleeps and our children come to play with their toys."