Peace of heart lies in perfect acceptance of God’s will. Only one thing is needed. True simplicity, the calmness that results from complete submission to whatever God wills, patience and forbearance toward the faults of others, frankness in confessing your faults, accepting reproof, and receiving counsel—These are the solid graces that will serve as helpful resources toward your sanctification.

Anxiety comes from not sufficiently accepting whatever happens as coming from God. From the moment you give up all self-will, and seek absolutely nothing but what He wills, you will be free from all your restless anxiety and calculating the future. There will be nothing to conceal. Short of that you will be uneasy, changeable, easily upset, dissatisfied with yourself and with others, full of reserve and mistrust. Your talents, unless chastened and humbled, will only torment you. But once you give yourself up to God, you will be at rest, and you will be filled with the joys of His Holy Spirit.
Never forget God’s will go hand in hand with prayer.
Jesus Prays at Gethsemane Mark 14:35-36
And He went a little beyond them, and fell to the ground and began to pray that if it were possible, the hour might pass Him by. And He was saying, “Abba! Father! All things are possible for You; remove this cup from Me; yet not what I will, but what You will.”