be a widely held myth
what does that expression mean in this sentence?
It is a widely held myth that material prosperity makes happy. In fact, a key factor that dictates happiness is social relationships.

Question

be a widely held myth
what does that expression mean in this sentence?
It is a widely held myth that material prosperity makes  happy. In fact, a key factor that dictates happiness is social relationships.

Answer

It means that it's commonly believed (everyone believes it's true), though not true (according to the author of text) that material prosperity makes people happy.

Answer

Yes, and in fact (so says the author) that it is human relationships that actually make one happy.

Answer

To be believed by many people. I think "held" here is short for "held to be true"

Answer

Mohammad has it right.  In English you hold a belief.  "I hold the belief that all people are good at heart."