Well I think a true gambler is when you made up your mind to withstand any outcome that might comes out along the line, without having any thought. Because is already obvious that gambling involves losses and winnings, so is quite sating that each of them can actually happens at any given time. So as a true gambler you would always accept any outcome without panicking because gambling is more of losing than winning.
When we panic about losing in gambling, it is because we are doing something wrong, that is, we are wasting money that should not be lost For this reason, before playing, it is better to establish how much money we can lose so as not to panic, because playing is enjoyable and it is not worth turning it into a nightmare.