John Cena says he's emotionally devastated after his breakup with fiancee Nikki Bella ... saying, "I love Nicole with all my heart and the split's tough."
The WWE superstar says he was expecting reporters to ask him questions about the split while promoting "Bumblebee" at CinemaCon in Vegas ... and decided he's ready to talk about it.
"It's a tough time but that's life," Cena said ... "We all go through highs and we all go through lows."
"I'm gonna get through it. I love her. I'll always love her."
"The fact that my heart hurts for her ... I know I was in love. So, I'll always have that."
Cena and Bella dated for roughly 6 years and he proposed at WrestleMania 33 in 2017.