I don't know if anyone can actually define true happiness as a general rule, because it varies from person to person.
For me it means that you know where you fit in the big picture and you know what you are supposed to do with your life.
You know who you are and you accept yourself totally.
These things, to me, are very close to having true happiness.
There are other things that make me happy, like my family, my friends, and so forth.
But true happiness is realizing where you fit in the world and being fine with it.
