At the B2B end of the market, it is pretty certain there are reliable actors motivated by ordinary interests in maintaining ongoing relationships with good clients.

At the B2C end, there probably reliable retail services but I suspect it is largely a market for lemons. https://saylordotorg.github.io/text_introduction-to-economic... And perhaps a non-trivial number of law enforcement operations as appears to be the case with hitmen.

Like any service, personal recommendations from assholes in your social network are probably your best bet. Good luck.