'Selling Sunset' Star Alanna Gold Says She Sees Wedding Bells in Jason's Future

"Selling Sunset" star Jason Oppenheim is serious when he says his new girlfriend could end his confirmed bachelor status ... at least according to costar Alanna Hall.

We caught up with Alanna while she was leaving the COSF Foundation holiday event at Balmain West Hollywood Wednesday night, where she gushed about how cute it is to watch Jason be smitten with his new love -- Oppenheim realtor Jessica Vargas.

ICYMI ... Jason was on Alex Hall's "Pretty Dirty" podcast earlier this month, revealing he's planning on marrying Jess. This was huge news because he's always been adamant about how much he was against marriage.

Alanna gushed, "I've seen a change ... just his whole demeanor when he's around her and with her. I think it's really cute. I hope they get married. I think it's really good for him, and I think they bring out the best in each other."

And as the nursery rhyme says -- first comes love, then comes marriage, then comes Jason and the baby carriage ... Alanna hopes.

She told us she loved the idea of there being a first Oppenheim baby ... "It'd be very cute. I mean, we have all the dogs, we need a little baby in there."

As cute as that would be, it may not be captured on camera. Many of the ladies have basically said they don't want to continue the reality show, but Alanna is still holding out hope.

"Every season, everyone says they're not going to come back, so I guess we'll have to see," she said.