[MyTrixie143]

I know it is a lot of money to lose but Emma's overall health and welfare is what is most important.

I have had to rehome a few adults (maltese) who turned out not to be breeding quality and I did lose a lot of money. You just have to live and learn.
But here is what I did and I suggest to try the same for Emma.

I advertised them in an ad stating that before they left to go to their new homes they would be spayed/neutered, no exceptions. The price of course was very low, just enough to cover the surgery and other costs.
After interviewing several people, I found the perfect couple. I had them pay the amount up front, of course with a contract stating that it was paid in full. I then used that money to get the dog spayed. After it was done from recovering they were then allowed to pick up the dog and take him home. During the recovery time they were allowed to visit, so they felt reassured about it all. Of course they knew all of this when they agreed to it. This way you know that the dog will be spayed/neutered and you will have the cost to do it.

If someone is interested enough in Emma, and truly wants her and only wants the best for her, it shouldn't be a problem for them to agree to this. If not, then they really aren't the best home for her.