The assurance that what you need will be met is a personal relationship with God as your heavenly Father. He knows what you need before you ask. Prayer is not designed to inform God. He knows all things. Prayer receives from God our Father. God our Father will provide. You may testify, "My God shall supply all of my need according to His riches in glory by Christ Jesus" (Philippians 4:19). That's what you need supplied.
Your need is God's opportunity to provide. His covenant name is Jehovah-jireh, meaning the Lord will provide. All of us have needs. Fear says, "No one is going to provide for your needs. You are a needy person with no one who can help." Faith says, "The Lord will provide."
Your greatest need is not physical nor financial. Your greatest need is spiritual. You need God. You need faith in God who provides. His covenant name among others is Jehovah-jireh, which means the Lord provides. He is your need supplied.
You need purpose in life. You need to know that your life counts. Believe that your life counts when it comes to God. He made you. His Son died for you. He has you in this world on purpose. He has given you talents and gifts to serve others. He will use you to meet the needs of others, and you will discover that what you need is supplied.