Devotion and commitment are the keys to happiness because that equates to submission. You submit to what you are committed and devoted to.
Submission is the opposite of resistance.
Submission is the opposite of dissatisfaction.
As Buddha said; “Life is suffering, suffering is caused by desires.”
Desires come from dissatisfaction with your current situation.
By being totally devoted and committed to something or someone, not just a little thing but something that impacts your entire life and future.
This commitment that you submitted to, whatever you are devoted to so you no longer have any desire for anything different or more, is the way we eliminate desires, and suffering.