When you proclaim bold promises of your product or service, and deliver it shows confidence and can create stronger relationships with the customer.
Reference
Ferriss, Timothy. The 4-Hour Workweek: Escape 9-5, Live Anywhere, and Join the New Rich. Expanded and Updated ed., 1st revised ed, Crown Publishers, 2009.
Highlights or timestamps
And, finally, your product should make a big promise – and deliver on that promise.
— ^b34679 from The 4-Hour Workweek
Such bold promises show your customers how serious you are about your product and give them the added confidence they need to make a purchase.
— ^f57575 from The 4-Hour Workweek