He said in an interview with Seventeen magazine: "I always want to be honest and let people know that those mistakes aren't who I am
The 'Baby' hitmaker is sorry for his recent conduct - which has included being arrested for driving offences, egging a neighbour's house and abandoning his pet monkey in Germany - and wishes someone had stopped his increasingly "cocky" behaviour.
He said: "I was getting cockier and cockier. I didn't have people to check me. I looked back and I was disappointed in myself. You have to own up to the mistakes,you have to say, I'm sorry if I've let you down. I turned a lot of people off over the past few years, but I know I can still turn out good music and turn everything all around.
"I've lost some of my best qualities. For that, I am sorry."
And the 21-year-old star insists his previous conduct doesn't reflect who he really is.
He added in an interview with Seventeen magazine: "I always want to be honest and let people know that those mistakes aren't who I am - Who I am is someone who really cares about people."
The 'Boyfriend' singer - who has previously dated Selena Gomez and been romantically linked with Kendall Jenner and Hailey Baldwin - is now looking for everlasting love with someone he feels "safe" with.
He said: "I need healthy relationships with people I can feel safe with people I can say whatever to, and I'm not going to be judged.
"In a girl, I want someone who's confident in herself and honest. I have to find her very attractive and as someone I can see myself with for the rest of my life."