In the end ink on paper doesn't mean that you're not scamming people. Fake hets these days are far less common than people think. Back when het pieds were 1500.00 for a female or het clowns were 2500.00 people were making big buck selling hets. But now days with many of the recessive animals being more affordable and hets bringing little more than most base morphs, I think you're safe.
I have quite a few hets that I never got anything with. I trust the breeder and know where they live if the animal doesn't prove out.
As a new breeder the thing you can do is have your stuff in order from the get go. Have pics of mom on the egg's and a clutch number. This way you and the buyer can keep track of exactly which clutch you say the animal cam from.
In the end it's your ability to establish trust with your customers.