Integrity is assured if you are up front with people.
This is the concept of early customers as stakeholders.
You can be upfront with people by saying, "Hey, I've looked into your needs and painful problems and I really want to serve you. I want to build this solution. But it costs money. Here's an example (show mark up) of what I have in mind. If I get x number of people to buy now, I'll build it. You can even get lifetime access (or some substantially reduced price) for taken on the risk and believing in me".
I think all those people who discount this method of serving customers are letting their fear of rejection get hold of them.
It's okay!
Fear is a natural reaction of the lizard brain; there's nothing to be afraid of.
But those of us that have tried this method and have seen how willing people are to work with you to build a solution (if your "heart" is in the right place, i.e. to serve them), know it works.
Seth Godin has a talk about "shipping on time" and just getting it out there to let the market decide (that's totally worth seeing).
(From ForaTV's channel, "Overcoming The Lizard Brain" - https://www.youtube.com/watch?v=XqozprFZ_38 )