"I never ever had problems with anger. No, no domestic violence with any of my past girlfriends," Brown said. "I never was that kind of person. ... I look at it, and it's really, like really difficult. It's like, 'How could I be that person?'"
Although some people have doubted his sincerity, Brown told Roberts he understands the severity of the incident and said he still has "love for" Rihanna.
"I think what it is when people see me smiling and kind of nonchalantly getting answers or, or saying things. It's -- I'm human, really, I'm like really hurting inside," he said. "And it really kind of like is devastating to me."
Brown also reacted to Rihanna's comments from her exclusive interview with ABC New's Diane Sawyer, when the pop star broke her silence about the night Brown beat her.
"He had no -- no soul in his eyes. Just blank. So, at that point, I just didn't know what could happen. ... There was no person when I looked at him. ... It wasn't the same person that says, 'I love you,'" she said in the "20/20" interview.
"I was wrong for what I did," Brown told Roberts. "And I would definitely say that it's not something that I look past or look over. Something that's really, really touchy. And, and like I said, I'm -- I'm really sorry for -- for what went down. And what happened."
Following Rihanna's interview on "20/20," the number of cases reported to the National Domestic Violence Hotline rose 59 percent.
Many women, like Rihanna, spoke about the wound that does not heal, something Brown said he understands.
"I can, I can see what damage it does, mentally, more than physical," Brown told Roberts.
Brown beat Rihanna during an argument after a pre-Grammy Awards party, while they were in his car parked in the Hancock Park area of Los Angeles around 12:30 a.m., Feb. 8, 2009.
Brown, 20, pleaded guilty to felony assault and was sentenced to five years of probation, community labor and one year of domestic-violence counseling for assault against his 21-year-old girlfriend.
At Brown's Aug. 25 sentencing, Los Angeles Superior Court Judge Patricia Schnegg ordered the singer to stay 100 yards away from his former girlfriend for the next five years, unless they are attending music industry events.
Watch the full Chris Brown interview on "20/20" Friday, Dec. 4 at 10 p.m. ET.