I know the song is about Nikki sixx getting off drugs and how its based off his book. He's saying that coming so close to ending his own life for good, he's learned how truly great life really is. And he's sending a message to others basically saying life is too valuable to risk over drugs and the things he's done. It took me a while to understand why he says "will you swear on your life that no one will cry at my funeral" and I think I've got it now. I think he means it rhetorically, knowing you can't promise that. Meaning that people love you. No matter who you are someone in this world cares for you. And to play risk and get yourself killed doesn't only hurt you. The momentary pleasure from the drugs isn't worth it. Life is too beautiful to give up. At least that's what I got from it.