There is no doubt that happiness is the most precious thing in the world.
Without it, life will be empty and meaningless.
If you wish to know how to get happiness, you must pay attention to the following two points.

First, health is the secret of happiness(the key to happiness).
Only a strong man can enjoy the pleasure of life.

Secondly, happiness consists in contentment.
A man who is dissatisfied with his present condition is always in distress.

　　*注释： precious 　adj. 宝贵的，贵重的，珍爱的
　　 　　　 contentment 　n. 满意，知足
　　　　　　distress 　n. 悲痛，不幸，忧伤

　　参考译文：

　　如何获得快乐

　　快乐无疑是世界上最宝贵的东西。
　　没有它，人生将是空虚的而且毫无意义的。
　　如果你希望知道如何获得快乐，你须注意下面的两点。
　　首先，健康是快乐的要诀。
　　唯有身体强壮的人才能享受人生的乐趣。
　　其次，快乐在于知足。
　　一个不满于现状的人总是处在痛苦之中。