Colleagues and so-called friends. Or he or she may double-cross you, pretending to keep your secret while working for your adversary. The person might deceive you into thinking that they are loyal to you by disclosing to you your adversary's secret. This way the person is trusted by both you and your adversary while they are working for neither but themselves. So, you can well imagine the perils of trusting anyone with your secret. 

A secret can be a secret thought, a secret wish, a secret letter, a secret meeting, a secret happening, a secret affair, a secret action, and any other kind of secret. This world is full of secrets and some of us believe that we've been born here to unearth the secrets of the Earth. Almost each of us has a secret that we'd like to keep firmly locked within ourselves. But it is hard to keep even your own secrets.