I'm curious to try this out, but I can't justify spending $97 for Nerva without any kind of trial period. A promise of a full refund isn't enough, unfortunately.
A money-back guarantee isn't compelling for me, for several reasons. First, I know that I would feel guilty asking for money back, and I want to avoid being in that situation. Second, I don't fully trust money-back guarantees. Third, that's ~$100 that I need to part with when I might see within 1 hour that the product is not a fit.