When verifying a pin with Pinterest the expectations are the same as any other social network. Make sure you upload a unique photo or video, add a link to the product, and add some unique text in the description.
With that said if you are verifying a content distribution campaign make sure to read any special instructions or just use the post now feature to push the content to your board. Here is more information about how to verify a content distribution campaign.
What content should go in your post
What if you are saving from a site?
When creating a pin if you are using the save from site feature make sure to add the product URL to your description (highlighted in red below).