When in early stage of a site how to do you convince a POTENTIAL customer that we are a startup we will do anything to ease them...but don’t feel like this is a scam

Because we don’t have content on the site, we don’t want customers to have scam like feeling.

Other way if you have some demo content and in the about page or as a title you can say this site is for beta test please leave what we did right, what we did wrong, and if you would have done that how would you do it ?

How tell people/customers at the early stage?