We understand that you are going through a trying time and are struggling with doubt and frustration. First, we commend you for coming to God in prayer and for acknowledging Jesus Christ the Savior in your prayer. It is only in the name of Jesus that we have access to the Father, and it is only by His name that we can be saved. "There is salvation in no one else, for there is no other name under heaven that is given among men, by which we must be saved!" WEB Acts 4:12.
Doubt is a common struggle, even among believers. In times of trouble, remember the words of Jesus, "Don't be anxious, saying, 'What will we eat?', 'What will we drink?' or, 'With what will we be clothed?' For the Gentiles seek after all these things, for your heavenly Father knows that you need all these things. But seek first God's Kingdom, and his righteousness; and all these things will be given to you as well." WEB Matthew 6:31-33.
Using vulgar language is not pleasing to God, as it says in Ephesians 4:29, "Let no corrupt speech proceed out of your mouth, but such as is good for building up as the need may be, that it may give grace to those who hear." WEB. It's important to ask for forgiveness, as you have done, and to strive to speak in a way that honors God.
When you feel hopeless, remember that God is faithful. "Let us hold tightly without wavering to the hope we affirm, for God can be trusted to keep his promise." WEB Hebrews 10:23. Even when the devil tries to plant seeds of doubt, know that "He who is in you is greater than he who is in the world." WEB 1 John 4:4.
We join you in prayer, asking God to forgive you and to give you the strength to trust in Him completely, "Lord, forgive our friend for any doubts and vulgar words. Strengthen their faith and help them to trust in you completely. Provide for their needs and the needs of their family, and help them to seek first your kingdom and righteousness. In Jesus' mighty name, we pray. Amen."
Continue to pray and to seek God's will. Trust that He hears you and that He will answer your prayers according to His perfect plan. Stand firm in your faith, and do not waver. As it says in James 1:6-8, "But let him ask in faith, nothing wavering. For he who wavers is like a wave of the sea driven with the wind and tossed. For let not that man think that he will receive anything from the Lord. He is a double-minded man, unstable in all his ways." WEB.
Stand firm, trust in God, and continue to pray in the name of Jesus. We are here with you in spirit, seeking God's will together.