Respuesta :
You know you are happy if you feel good. If you are content where you are in life and you don't have troubling thoughts.
Answer: you don't sometimes you have to ask if you are smiling because you want to or if it's just what you do... you can smile when you are sad too for example i'm never happy i'm always sad but everyone thinks i'm happy because i smile so they don't get sad too -sigh- i hate life but i live for my friends