Well of course they wouldn't advertise these sorts of practices in their pricing plans. But you can get certain hints from some of the verbiage. For example, they talk about "review invitations" -- this is code for review gating, which is the practice of selectively inviting users who are more likely to leave positive reviews.

They also say "Curate your Trustpilot Company Profile Page through ... adding authentic content". The term "authentic content" is code for "positive reviews", because you'll be able to flag any negative reviews as inauthentic.

And of course you can also look at reviews of Trustpilot itself from third parties, i.e. websites where Trustpilot doesn't have a paid/boosted account, for instance: https://www.reviews.io/company-reviews/store/trustpilot