It can work both ways, you can know someone that you can trust with that secret. And then you can not know someone and be cautious because they will tell people what you said to them and you don’t know how trustworthy they are.
And the other way is you know someone and they tell you the secret, the risks are that they tell people that you know or they know or they blackmail you with it. Then you tell a complete stranger and they won’t care about your secret because they don’t know you.