RTP is the abbreviation for return to player. This basically shows the wagered amount that players will get back after a certain period. It is important before you play to look at the RTP because the higher it is the higher the return will be.
For instance, if the game you are playing has a 96% RTP rate, it simply means you and other players will be getting 96% returned to you.
By so doing you will not regret your decision whatsoever. Play now and enjoy!