Happiness...
I had a friend ask me last night "how do you know if you're truly happy?" How do you answer that? I can only answer based on my experience.
I know that I am truly happy because I look forward to each day that I get to spend with my husband. I still get butterflies when I see him after a long day apart. I can't wait to see him at the end of the day. He knows what I need to hear, even if I say nothing at all.
He pushes me to be the person that he knows that I can be every day. He knows me better than I know myself...and knows exactly when he needs to back off or when I need a little push in the right direction. He's my rock...
I guess I don't really have an answer about how to know if you're truly happy...I just know that I am :)