City chief executive Ferran Soriano stated Bonucci contacted the Premier League club to sound out their thoughts over a potential move, although Juventus were not keen to sell.
Bonucci signed a new contract that runs to 2021 in Turin last month and he has his sights on adding European success to Juventus' domestic domination, although he told Corriere dello Sport he also had his head turned by Barcelona.
"Saying no to Barcelona and Manchester City was not easy," he said. "How could it be if wanting you was the best coach in the world.
"I made the decision pondering everything. It was not a choice I took lightly because Interest came from Guardiola, who is the best there is.
"But now I am happy to be at Juventus and I want to win in Italy and begin to do so in Europe.
"In Serie A we must never take anything for granted. In Europe we need a decisive attitude and with this form and [head coach Massimiliano] Allegri I'm sure we can go all the way."
Bonucci also addressed the furore surrounding Juve forward Paulo Dybala refusing to shake Allegri's hand when he was substituted during Sunday's 2-0 win at Sassuolo.
Dybala has four goals in six appearances since the turn of the year, having initially struggled for last season's prolific form this time around.
"Paulo realised that he had been disrespectful to the whole team and to the club rather than to Allegri," Bonucci added.
"He apologised and we have forgiven him because he is young. He wanted to give more in the game against Sassuolo.
"That is why he reacted that way. Dybala is crucial for us."