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.
I will not bet on the same player at sports betting. It will not ensure my profit, because we know that the aim of all of the gamblers either win sone profits, or play for fun and spend their time. Maybe you just play for fun, i respect that, but there are many gamblers that really play for profit. And i dont see a way of profit from what youve said.