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Positive and reliable ratings for me are already enough.
Rating sites don't seem very credible as a basis for trust, let's call it the most popular Trustpilot. Ad managers may employ sockpuppets to provide false ratings and reviews.
I even prefer to read user experience reviews on this forum as my main consideration for choosing a casino, where customer service is also a discussion.
Reviews should really not be your basis, its bette to analyze it on your own and experience the whole thing by yourself. If you still believe on a good platform that pays fairly then you should do your part as well. To lessen the stress of doing this, you can try to gamble on the top gambling site and you can easily know if its worth it to play with them or not.