The honesty of a random number generator is difficult to verify directly, but it is possible indirectly. Pay attention to whether the site contains information about checks, reports on algorithms, or mentions of testing. Also, the stability and adequacy of the game over time is a good sign of honest work.
An honest random number generator is, of course, difficult to test yourself. But I've been looking at how often people win, and whether there are any complaints about fraud. The https://casinocasimba.com/ website was recommended to me on the forum — there are no problems with this. I'm not an expert, but if the casino was manipulating the results, people would quickly notice it and leave. I like playing there because everything seems honest and transparent.