Trust and marketing never belong in the same sentence. Marketing is the art of inconsequential "pushing of the truth" and frivolous claims. It's the art of shoving a sub-par product in your face over a relevant product.
What would you call it when someone, say, the product creator, speaks the truth about a product to get the word out? That would fall under "marketing."
"Marketing" is as general a term as "programming." There are all sorts of bad things accomplished with programming, but I think you'd agree that generalizing all of "programming" as something negative would be ridiculous.
The best that marketing can do to convey trust is to use social proof. After all, if everyone is using Brand X, it must be good, right? Of course, social proof can be faked, exaggerated, or bought with a lot of money, as is commonly done.
To continue with my analogy, it's like saying "spam is bad, therefore all email is bad, and email is created by programming, therefore all programming is bad."
Not a single product that was spoken about had a genuine impact on the buyer? Not a single product actually worked as advertised?