I heard that some bounties fail to pay participants at the end of work. Considering this senerio, how can one know which bounty is a good to participate in?
First you have to know the level of trust of the bounty management manager, because those who have a good reputation, rarely do anything related to failure to pay, unless they fail to be paid by the project owner, it's not entirely the manager's fault.
This is what you have to distinguish, failed to be paid by the project owner or bounty manager (Manager)