ET caught up with the 40-year-old WWE star at the Daddy's Home 2 junket and premiere in Los Angeles over the weekend, where he marveled over his fiancée's journey on the dance competition show -- and how she handled getting booted off during week seven.
"I thought she handled it great," Cena told ET's Kevin Frazier. "I think I handled it worse. I was very shocked, I was filming nights on Bumblebee, so I couldn't be there. I tried to be there as much as I could for her, and I guess, in hindsight, I wish I was there more. I don't know if it would have helped or whatever, but I wish I was there, especially in that moment."
"I think it was shocking to everybody that watched the show," he continued. "I think when you watch the program, the goal is to take someone who doesn't know the skill and watch them develop over the course of time and I know she walked into that with two left feet. We used to dance together and just do the awkward prom dance, that's all we got. And man, in the arc of seven weeks she became a beautiful dancer, so I can speak for myself and say that I was extremely shocked."
Despite the fact that Bella didn't make it to the semi-finals, Cena says her time on the show was well worth it.
"I thought she danced so beautifully," he gushed. "She took risks, she really was bold, she had moments of humility. She gave it her all and I think when you put that much into something, it doesn't work out the way you want, you can't have any regrets about it. So, I was just constantly trying to tell her that message."
The lovebirds are gearing up for their upcoming nuptials, and Cena already knows that Bella will "be good" when it comes time for their first dance.
"I think I might just stand there and do like a teapot thing and let her do all her stuff," he joked. "Hopefully I can step my game up by learning piano or learning two-step or something."
Cena continued on, telling ET that the rest of the wedding planning is basically all up to Bella.
"I think I will be told what I'm going to wear for my wedding," he said. "I can tell you what I'm wearing on my wedding night... birthday suit!"
"I think a lot of the details with the wedding [are up to her], going back to more serious, because I want the day to be very special for her," he added. "I just want everybody to have a fun time, but I want the day to be special for her, so the little details like that, if I'm told what to wear, I'll fit in just fine."
"I've set a date, I found the dress and now I have to do all the in between," she explained, revealing that her dress is Marchesa. "Once I got engaged, I started to realize, like, 'Oh, I'll be married forever, so I want a long engagement.' And I just want to enjoy being a fiancée. I want to enjoy the wedding planning process... I know I'm not going to get cold feet, so I just really want to enjoy it."
Hear more from that exclusive interview in the video below!