Are you ever afraid to share your faith? You have a lot of company. The Apostle Paul who normally was fearless must of had a doubt when the Lord spoke to him.
One night the Lord spoke to Paul in a vision: “Do not be afraid; keep on speaking, do not be silent. For I am with you, and no one is going to attack and harm you, because I have many people in this city.” - Acts 18:9-10
Joshua had doubts in His ability to lead God's people in to the Promise land. God said to him, No one will be able to stand against you all the days of your life. As I was with Moses, so I will be with you; I will never leave you nor forsake you. Be strong and courageous, because you will lead these people to inherit the land I swore to their ancestors to give them. “Be strong and very courageous. Be careful to obey all the law my servant Moses gave you; do not turn from it to the right or to the left, that you may be successful wherever you go. Keep this Book of the Law always on your lips; meditate on it day and night, so that you may be careful to do everything written in it. Then you will be prosperous and successful. Have I not commanded you? Be strong and courageous. Do not be afraid; do not be discouraged, for the Lord your God will be with you wherever you go.” - Joshua 1
His response - So Joshua ordered the officers of the people: “Go through the camp and tell the people, ‘Get your provisions ready. Three days from now you will cross the Jordan here to go in and take possession of the land the Lord your God is giving you for your own.’”
Keep your focus on God. He will give you the words to say, and directions on where to go.