Strong determination is one of the five strengths that allow us to practice our bodhisattva discipline of helping others throughout our whole life. It is connected with developing an attitude toward your meditation practice that is almost like falling completely in love.You have a sense of appreciation and joy; therefore, your practice does not become torture or torment; it does not become a cage. Instead, your practice becomes a way of cheering yourself up constantly. The idea is one of waking up basic goodness, and realizing that you are in the right spot, the right practice. So there is a sense of joy in strong determination.
Condensed from pages 71-72 in Training the Mind and Cultivating Loving Kindness.