You can bet your life 也可以表示肯定，can 可以省略。这个表达也可以当成一种反讽，如果某人说的话被现实情况打脸了，他的朋友就会对他说 You can bet your life.

【例句】
You can bet your life that she will arrive here on time.
她肯定会准时抵达这儿。

Oh, you can bet your life that he will go to this party.He went on a business trip yesterday.
噢，你肯定他会来参加聚会？他昨天出差了。