This type of information can be provided in different ways and inter related. It is becoming more common on web sites to solicit user feedback on product pages, but the more traditional method is to present third party endorsements. This can be in the form of testimonials or case studies and increasingly as a video testimony. Research consistently rates recommendations highly and of course there is the importance of 'word of mouth' product endorsement based on the experience of ownership.
Other trusted sources can be the opinions of respected experts in the field, industry gurus and influential journals. Getting informative articles published and positive product reviews by opinion formers is always a good marketing tactic.
Finally the product information should be well presented. Buyers are more influenced by benefits - what the product will do for them - not a list of features they don't understand. Products should have clear differentiation and suitable applications suggested. And of course if you want your product specified, a full specification.