You are right to cling to that promise: with God, all things are possible. Not as a vague wish, but because the Lord Himself has spoken it, and His word cannot fail. That is exactly what faith does: it lays hold of what God has said, even when every visible circumstance screams the opposite. Faith is the substance of hope, the confident assurance that what He has promised He will perform.
And what you are asking for is so close to His heart. You long for a resurrected heart, a restored soul, a life, faith, hope, and joy that are not merely mended for a season but made permanently whole. Humanly, you see it as impossible, and that is the best place to be, because then you are driven to Jesus Christ as your only hope. Your hope for forgiveness, for standing before God, for deep fellowship with Him, lies entirely in His finished work.
Notice how your own request centers on the heart, the soul, the inner man. That is where God always begins. He is not impressed by outward displays that mask an unchanged interior; He says, "Rend your heart and not your garments." A change that only touches the surface will postpone the problem, but it will rise again. What you need, and what He delights to give, is a work of His Spirit deep within. Cry out to Him, "Unite my heart to fear Your name." So often our hearts are divided: we desire God's will, yet we also feel the pull of our own wants and the weariness of a long battle. That divided state makes us unstable, wavering. But when He fixes our heart on Him, there is a singleness of purpose that no longer vacillates. Pray with the psalmist, "My heart is fixed, O God, my heart is fixed." That is not something you achieve by grinding determination; it is something He does as you yield to Him.
The word of God is essential for the development of faith within your heart. Some wish they had more faith, but the path to stronger faith is not to stare at your own emptiness. Faith comes by immersing yourself in what God has said. His word is near you now, in your mouth and in your heart, that is the word of faith we preach. So go to the Scriptures expecting Him to give you a living promise. There you will find strength, confidence, and a place of rest. Your faith will be built as you simply take God at His word, believing it because He said it.
And remember, true faith will produce a changed life. Not overnight perfection, but a growing conformity to what you believe. The faith that saves is never alone; it works through love. As He resurrects your heart, evidence will follow, perhaps quietly, perhaps gradually, but truly. That is not you striving to earn anything; it is the natural fruit of a living faith.
Hope, too, is vital. It is a combination of desire and expectation. You desire restoration, and you can have expectation because the God of hope is at work. He does not dangle promises to taunt you. He is patient, and He will fill you with all joy and peace in believing, so that you may abound in hope by the power of the Holy Spirit. When your soul is cast down, that hope becomes the anchor that keeps you. It looks forward to what is promised, the blessed appearing of our great God and Savior, and the certainty of eternal life, and in that light, present darkness loses its grip.
Do not be dismayed when you fall short. What the Lord sees is the heart. Your heart may be wholly toward Him even while you lament areas of failure. Like Peter, the spirit is willing even when the flesh stumbles. That very awareness of how far you come short is meant to drive you back to Jesus Christ, not to despair. He is your righteousness.
You asked for prayer, and I am praying. May God, the God of patience and hope, take hold of your heart, unite it, and fix it steadfastly on Himself. May He resurrect every dead place and restore your soul, your faith, your hope, and your joy, not as a fleeting emotion, but as the deep, enduring gift of His presence. The word is near you. Hope in Him, for with God all things are possible.