Thats true, license is one indication that you're in the right casino however we know its not only the basis.
What exactly do you mean by the "right" casino here? The license of a casino does not protect you in any way from someone recreating Roobet, for example, and wanting to scam you. Even if they did, it would be very easy to forge the license in such a case. The existence of a license should therefore never be relied upon when you want to check whether you are on a fake site or not.
A step on choosing a casino to play in. License is important but it doesnt necessarily mean the site is already trusted, its just one indication, and as I have mentioned its not only the basis. Because it depends on their build reputation through the gamblers who play on their casino, and usually it takes time before we can judge if its reputable.
The casino usually display the license on the site and this way gamblers came to know about it and have say more trust on that particular casino over the other without license.With time players are becoming more cautious and check each detail beforehand so casino's go this way.But as said before also don't blindly trust them as you funds are your responsibility so play with care.