Mario Mandzukic and Dani Alves were on target as Juventus defeated Monaco 2-1 in Tuesday's semi-final second leg in Turin for a 4-1 aggregate triumph.
Mandzukic and Alves scored in the first half to help the five-time reigning Serie A champions reach the competition's final at Principality Stadium on June 3.
Italy international Bonucci said a more mature Juventus – an immovable force in Serie A as they seek European glory – have shown they belong on the big stage, having lost to Barcelona in the 2014-15 Champions League decider.
"It's a great result and what a big club have to do, challenge for three trophies. We have grown a great deal over the last two years and I think Juventus are now a certainty, not a surprise," Bonucci told Mediaset Premium.
"The goal we conceded today was really annoying. We cannot concede like that when distracted. It had been in the air for about 10 minutes, we were letting them run past us.
"We have to improve and learn from that, as in the Champions League you can't get distracted for a second.
"The important thing is that Juventus go to the final in Cardiff and are confident we can take the trophy home.
"This is now a mature team, aware of their capabilities. In Berlin we had a magnificent midfield, but we're certainly no worse off now. We're loving the new system, so we just have to go to Cardiff and play the best game in the history of Juventus.
"The change of system made us feel more European, only as long as everyone worked hard off the ball. That made us even more united. We are solid at the back and almost always manage to score upfront."
"This is a wonderful night for everyone. We've achieved a dream we had since pre-season in Melbourne, we played so many games and it's not over yet. We want to win the final.
"I hope to be decisive in my team's victory. We have many games before that and other objectives too."