Proof second: evidence before the price feels high
Proof belongs early, because doubt arrives early. As soon as a buyer understands what a product does, they ask whether it works, whether other people like it, and whether it suits someone like them. Reviews, ratings, before and after context where it is honest and permitted, usage detail, and ingredient or material transparency are all proof, but only if they appear while that doubt is live. Proof buried at the bottom of a long page answers a question the buyer already gave up on.
Proof should also match the product. A skincare product needs routine and suitability proof: how it is used, how often, and for which skin concerns. A fashion product needs fit and material proof: how it drapes, what it is made of, and how it fits real bodies. A kitchen product needs construction and size proof: what it is made of, how big it is, and how it is cared for. Generic proof, such as a single five-star badge with no detail, answers none of these doubts properly.