Marketing by its very nature demands that you have a firm and steady belief in the product you represent. You have to count the product as so valuable that it would make no sense to keep the product away from those who would most benefit from the product.
Obviously greed can be a motivator in marketing, but it will not be a sustainable motive. You may, in fact, need to hire others to help you market the product if your sole objective is the accumulation of wealth.
When you stop believing in a product you will also find a parallel decrease in your enthusiasm for marketing.
Why is belief in a product so important?
Primarily it has to do with the transference of trust. If you have built a reputation for integrity you will not be satisfied in selling a product that you do not believe has intrinsic value. For this type of business owner it may feel a bit like false advertising to attempt to sell a product you are not 100% sold on yourself.
When you can demonstrate a high level of belief in a product you issue a transferable statement of trust. You will be more passionate about how you present the product and you will have no reservations...