You can never have too much proof but...
This can be a chicken and egg scenario to start with.
You're trying to sell your product, but you need proof, but nobody's bought your product.
So you can't get proof.
How do you break this vicious cycle?
One way is to offer your product for free, in exchange for somebody giving you an honest testimonial.
You need to make sure you're not giving your product away, in exchange for a positive review.
You don't want to be seen to pay, or bribe people to say the right thing...
You merely want beta testers to give you their honest feedback.
Once your offer is ready, you can reach out to your target audience, and offer a limited number of places or units for free.
All you ask in return, is they give you their honest opinion about it.
This way you can get proof and testimonials right out of the gate before you've even done sales.
The key then, of course, is to leverage and build on this momentum.
"Encourage your customers to submit testimonials and case studies by including links in the members area and email your list asking for success stories."