She's built for fun.
I don't blame John for not putting a ring on her finger. The limited time I've seen her outside of RAW/Smackdown programming, she's given me a completely different vibe than Bri.
Scary thing for Nikki is that she's gotten her body tailor made especially for the purpose of snagging a top guy with a lot of bread like Cena.
Wasting her prime trying to get Cena to lock it down.
New crop of guys coming in and to them, she'll be the equivalent of the old chick hanging out at the club.
She's bad af though so someone will eventually wife her up.