It's mysterious because it has two meanings. Both meanings will help you get more business from any promotion you do. Think about this in your own life. When you need an accountant, or an attorney, or a doctor, or for that matter a hardware store in a new town, you'll probably turn to someone you know, whose judgment you trust, to refer you to the service or product provider you're looking for.
People are always on the lookout for sources of advice they can trust.
By putting testimonials and case studies in your copy involving people who will fill the role of trusted friends and advisors. Because they haven't put enough productive effort into the research that pays off. There's another, equally important meaning. Before I tell you what it is, let me give you a big, fat hint. And it applies to marketing and selling.