Yes, there is. It's called arbitrage betting.
Essentially you are simply taking advantage of different competitive prices that different bookies may offer at the same time. You bet x% of your balance on one outcome and x% of your balance on another - if you win either of these outcomes then you are guaranteed to win a fixed percentage of profit. It's basically +EV gambling. But right now these odds are quite hard to find.
it works only on sportsbetting isn't it?
you will have no chance to lose with this arbitrage betting , as you bet on both sides ,
more than just a safe method actually , you just need to have a wide network ,
you need more than 1 sportsbetting account, it is not big deal i can say yes this is the safe methodin sportsbetting.
Arbitrage betting only works in sport betting but the idea behind it, arbitrage, is nothing new and can be used to earn money anywhere, if for example you found a great offer of a product and you knew that in another store they were buying the same product for a bigger price, you could buy all the product and then sell it immediately for a profit.