One technique that you might want to consider is the "lift letter." This is a technique that comes out of old-school direct mail marketing, but may still have applications for your copy.

In traditional direct mail, the lift letter tends to be a separate envelope or piece of folded paper – usually a different color, that says: "Read this if you decide not to order."

The letter inside would contain some additional sales messages intended to convert skeptical readers. It would be written in a handwriting-style font, and would be intentionally folded to make it look like someone wrote a personal note. The goal of the lift letter is a last-ditch effort to overcome the doubts of any fence-sitting prospects.

In the online world, a lift letter is a button at the bottom of your sales page that sales "Still not sure?"

It takes the reader to a page with additional testimonials, that mentions that these people faced the same dilemma that you had, but finally ordered. And of course, they are pleased that they did.