The couple split following a fight in 2009, which left the pretty singer black and blue and Brown facing assault charges, but they reconciled last year (12) and spent Christmas and New Year together.
Brown also recently joined the Umbrella singer in Hawaii for her 25th birthday celebrations.
Now Rihanna has told Britain's Elle magazine that the romance is getting serious - and it's so much better the second time around.
She tells the glossy, "We got a fresh start and I'm thankful for that... Right now that's what we want, a great friendship that's unbreakable. Now that we're adults we can do this right."
Addressing the controversy surrounding her decision to take Brown back after what he did to her four years ago, Rihanna adds, "I have my own reasons, very, very private reasons. Very personal... (but the) bottom line is I know him. I had a lot to think about and I had a lot of time to think about it. I was trying to do this for myself.
"You don't have that feeling with everybody so when you have it you don't want to let go of it. I would definitely say that he is the one I have that kind of relationship with."
And it appears the We Found Love singer is making family plans with her beau, telling the magazine she has every intention of becoming a mum.