A really great presentation may cause a "fence sitter" to get off the fence.  But, if you rely on your presentation to convince, persuade, entice, or motivate a prospect to buy your product or service, you put too much pressure on yourself and your prospect.

Conceptually, prospects should be "sold" before you make your presentation.  They must develop a view of your product or service as the best fit for their problem, need, or challenge during the development process.