To know the fruit of efforts will surely come is to remain happy and healthy.
Expression: To know that the fruit of my effort will eventually come one day is to understand the importance of making effort. Once there is this understanding, it becomes easy to continue making effort, which is like nourishment that keeps one happy. So effort is never stopped till what has to be achieved is achieved.
Experience: Knowing that my effort will surely be fruitful makes me enjoy everything I do. It makes me remain happy, keeps me enthusiastic and free from tiredness, even when things are not going right for me. My mental happiness and well being thus keeps me healthy.