If you want to set up a co-hosting service it's like any other business. Put together a business plan to identify what you offer and how it's different/better than your competitors. Then develop a marketing plan to help you identify how you are going to market your service to hosts you've identified as your potential customer base @Jess5376
You say you've been a host (although I can't see this on your profile).
If you want to host in Costa Rica you will need a decent level of Spanish.
You are right most hosts understandably prefer to work with cohosts who have extensive experience as hosts themselves, good contacts with local trades people and cleaners and a good understanding of any STR regulations that apply to your location.