All the casinos recommended in the replies above are reputable casinos. There is no such thing as a completely safe online website, be it a casino, exchange, wallet..
Take your time to read the announcement threads on this section then make up your own mind. You are the only one who can tell which is the best casino based on your own preferences.
Well being reputable does significantly reduce the risk (but not remove it completely) of the chance of the casino being a scam since well, they already have a solid user base which thereby creates a pretty solid reputation for them, both security-wise and reputation-wise. It also makes it a lot easier to find some info to crosscheck since there'd probably be tens of cases where the casino was involved, either with users being irresponsible or with legit cases that were caused by mismanagement or bugs, finding those kinds of situations is in a sense kind of a review that can make you be at ease since you know the casino answers.
Pretty sure preferences about the UI/wallet/games comes after that tbf.