where? editors-r-us?
How do unknown authors prevent an editor stealing their idea?
You have to find a professional editor who has integrity.
If you don't know where to find one be inventive and call a writer or a university English department and ask where you could find a good editor. Also, any writer's association will have editors who will hire out their services.
The difference a real editor can make can be tremendous.
When you have your writing edited then you can hire someone to do all your graphics for you. Again it can make a huge difference. And it will be worth the price.
“How do unknown authors prevent an editor stealing their idea?”
They spend $35.00 on copyrighting their work.