Don't guess. Guessing is an appalling habit. It shows laziness of mind. One either knows or doesn't know. If you know, speak of a certainty. If you don't know, be man enough to say you don't know, and then research the question until you do know. Anything else is unacceptable.

You're born, you live and you die. There are no do-overs, no second chances to make things right if you fuck 'em up the first time. Not in this life anyway. You make your choices and you live with them. And in the end you are those choices.