Los Angeles, March 28 (IANS): Singer Chris Brown says he had to prove himself to girlfriend Rihanna that he is a good guy and a changed man now.

Brown and Rihanna parted ways in 2009 when he was accused of physically assaulting her. He was sentenced to six months of community service.

However, the couple reunited again and went public with their relationship earlier this year, reports thesun.co.uk.

"It's all about my responsibility. I just tried my best to be the best man I could be over the years....show her how remorseful and sorry I was for the incident, and that time was probably the worst part of my life...she is a wonderful person. I'm eternally grateful and thankful," Brown said on a US chat show.

Rihanna was criticised for trusting Brown again, but he says people can think whatever they want to.

"People are entitled to their opinions. I can't go around blaming. It's all about my responsibility and me growing up as a man," Brown said.