If your product ratings are not showing in Google Shopping please check the following:
✔️ You have a Google Merchant account.
If you do not have a Google Merchant Account, head over to the Google Merchant Center to set this up.
✔️ You have 50+ reviews
If you don't have more than 50 reviews, you cannot use the Google Shopping feature.
✔️ You have been approved for a product reviews feed.
If you don't have a Product Reviews option you'll need to fill out the Product Ratings Interest Form.