There are a few reasons why your paid stars (Seller Ratings) might not be displaying:
Do you have more than 150 reviews?
The minimum review threshold for Seller Ratings is 150. This means, to become eligible for Seller Ratings, you’ll need a minimum of 150 unique reviews in the past 12 months, and an average star rating of 3.5 or more.
Historically, the number of reviews to collect to be eligible for Seller Ratings was 30. However, Google changed this threshold as of August 2016.
Availability by Country
Google Shopping ads can appear on Google Shopping, Google Search, and some Google Search Partners in these countries: Australia, Austria, Belgium, Brazil, Canada, Czechia, Denmark, France, Germany, Italy, Japan, Mexico, Norway, Poland, the Netherlands, Russia, Spain, Sweden, Switzerland, Turkey, the UK, and the US.
Google Shopping ads only appear on Google Search in Ireland, Malaysia, New Zealand, Portugal, Singapore, South Africa and United Arab Emirates. In India, Shopping ads only appear on Google Search and some Google Search Partners.
Google Shopping ads are in beta for Argentina, Chile, Colombia, Hong Kong, Indonesia, Philippines, and Taiwan. If you sell products to one or more of these countries, you're invited to submit products and participate in the beta.
For more information on your country guidelines please call 0800 169 0409 or refer to the Google Requirements.
Are you using the right campaign type?
Seller Ratings are an Ad Extension which means they will only show if your campaign type is set to ‘Search Network’ or ‘Search Network with Display Select’. You will also need to ensure that ‘All Features’ has been selected.
Check your Seller Ratings are displaying
To check if your reviews are being sent to Google and are being fed into your Seller Ratings you will need to visit the following link: https://www.google.com/shopping/seller?q=example.com. You will need to change ‘example.com’ to be your website’s URL.
If Seller Ratings are not available for your website, this means your reviews aren’t feeding into your Seller Ratings. Please speak to your account manager to check this.
I have met the criteria for Seller Ratings but they still aren’t showing. What should I do?
Seller Ratings are also shown at Google’s discretion. However, if you would like some further advice on why they might not be displaying, you can call a Google Account Manager on 0800 169 0409.