"Tres pueden guardar un secreto si dos de ellos están muertos"

Simplified Meaning:

Keeping a secret can be very difficult, especially when more people know about it. Imagine you tell two friends a secret. Each friend might eventually feel the urge to share it with someone else they trust. If everyone keeps sharing, sooner or later, the secret is out. For instance, think about having a surprise party. The more people you tell about the party, the higher the chances someone will slip up and mention it to the person you're trying to surprise. To really keep it a surprise, it's best if very few people know about it. So, if you want to make sure a secret stays hidden, you have to limit how many people know. The quote humorously suggests that it's almost impossible to keep a secret between three people because humans naturally find it hard to stay completely silent about interesting information. To apply this to your life, be very selective about who you trust with confidential information. The fewer people you tell, the safer your secret will be.