This is a great truth, one of the greatest truths. It is a great truth because once we truly see this truth, we transcend it.
Once we truly know that life is difficult - once we truly understand and accept it - then life is no longer difficult.
Because once it is accepted, the fact that life is difficult no longer matters.
Source: The Road Less Traveled, 25th Anniversary Edition : A New Psychology of Love, Traditional Values and Spiritual Growth