Hi everyone I’m hoping someone could give me a bit of advice!
I’m trying to bond my 2 rabbits(one Flemish named Waffles and one silver marten named Soura) and Its been nearly a month and its just not working.
I have had a Waffles for 6 months and I recently adopted Soura from the SPCA.

It’s a male and a female and they’ve both been neutered/spayed. Waffles is cage free in my living room and Soura is staying in a pen in the living room. Waffles is a very friendly rabbit (will greet strangers at the door like a dog) and is very needy and affectionate. Soura is very suspicious of humans and fearful(I suspect her last owner wasn’t too kind). 

The first 2 weeks, I tried the bathtub but Soura kept being aggressive as soon as she sees waffles and it always always ended up in a fight. Waffles became quite stressed from these sessions so I decided to change it up. I tried the hallway outside the living room and here Waffles started being very aggressive and Soura became fearful. These sessions also ended up in a fight. I have also tried stress bonding but neither of them would seek comfort in the other one in times of stress.
So my question is – what do I do? I’m growing more and more pessimistic that they could ever live together but I really don’t want to return Soura to the SPCA.

EDIT: things I have tried: swapping litter boxes, swapping toys/towels. They also always eat their greens side by side. 

They seem to like each other when theyre in their respective cages – they even lay next to each other through the bars at times. However, it is when they meet outside in a neutral territory that they fight on sight.