Mariah Carey isn't ready to talk marriage to James Packer just yet ... at least not publicly.
Mimi dined out Monday night at Mastro's in Beverly Hills where our photog pretty slickly tried to get the scoop on whether she and her billionaire boyfriend are getting ready to walk down the aisle.
Check it out ... her response is hardly convincing. She did sound excited about her new track with French Montana and Justin Bieber -- but she's not getting new rocks out of them.
Nice try, MC ... but we know who's really buttering that bread.