I can not name any gambling site on which it is possible to always receive a win as it depends only on luck. Now you can use any crypto currency for the game, but do not spend all coins on entertainment.
You can not name any gambling site on which it is possible to always receive a win because such gambling sites never existed. Victory is not determined by the site but is determined by how lucky we are in gambling. That's it, none of the sites can make us always win.
Exactly, no any site is exist, where possible we get a win without helping the luck. Rules and regulations will be different but the way of winning is same, we win behalf of our skills and luck, we have skills but luck we have it or not, we know it on the result of betting. If we win then it mean we have luck in this bet but if we have lost then clearly everyone know that no luck.
If we think a little deeper, our victory means someone's defeat. So practically it is not possible for gambling sites to make every customer happy all the times he plays.
Still, if they are helping some specific gambler every time then the other customers will leave the game who will be his opponent. It is good to enjoy the game without dreaming about making money and hard efforts.