Your poor girl. Good thing you rescued her Usually it’s highly recommended all buns involved be fixed. Unspayed females are notoriously aggressive and territorial towards other bunnies and their living space, making it almost impossible to bond. Not only that, but fixed bunnies can often times feed off the hormones of an unfixed bunny, causing hormonal behavior in them as well. Ultimately it will have to come down to their personalities in this case and really going through the proper bonding process and taking it slow. But you should be prepared to have two separate bunnies because the odds are stacked against you.

Only advice is what A&B said above…. take it SLOWWwwwwwww… Lots of pre-bonding (read the bonding section of this website – swapping items and then swapping their whole cages) for at least a month… watch for them to no longer show any problems with the other one having been in their area, or being in theirs.
So no marking things by chinning them a lot and no territory pooping and peeing…
Watch for them to start mirroring each other – Grooming themselves / eating / things like that – at the same time.

Then start your sessions in 100% neutral territory – somewhere that neither of them have ever been before and out of smell range of their home turfs.

But start with the pre-bonding. Once you see the above mentioned good signs then you can re-post about wanting to start their dating sessions and people can help you through that then.

And good job rescuing that poor baby!

100% agree with Nutmeg’s advice. Good luck with the neuter!