One, Rose knows Spinel, so she knows what she's capable of, unlike Garnet and co. who were caught off guard by her battle tactics. Two, Rose's Sword is easily capable of poofing Spinel, which can lead to an easy capture via bubble. She only needs one hit in order to take out Spinel, just like Spinel only needs one hit with the Rejuvinator. Also, on the topic of the Rejuvinator, Rose should know about that as well, as Bismuth stated that the Diamonds used them to bring rebellious gems back in back to how they were originally, so she should be familiar with the concept of the Rejuvinator. So, despite the fact that, like Steven, it'll cut through her shields like jello, Rose'll be able to react to it accordingly. And also, Rose's Sword can easily be used to counter it, so she'll have a way of deflecting it away as well as being able to dodge.
And, as Cal said, Rose has a huge battle experience edge over Spinel, and I feel like this, along with all of the aforementioned counters to Spinel's advantages, leads me to believe that Rose will take this in the end, after a very hard-fought battle.
