I suggest that you stop feeling guilty about any insufficiency you think you have in sharing the gospel. Rather, pray for opportunities.
Be open about your faith in Christ. When the occasion presents itself, speak of His life, His teachings, and His incomparable gift to all mankind. … Share His powerful truths from the Book of Mormon. He has given us this promise: “Whosoever … shall confess me before men, him will I confess … before my Father … in heaven” [Matthew 10:32].
I promise you that as you pray often and sincerely for opportunities to “stand as a witness of God,” those opportunities will come, and those who seek more light and knowledge will be put before you. As you respond to spiritual promptings, the Holy Ghost will carry your words to the heart of another, and one day the Savior will confess you before His Father.
Please don’t see your efforts to share the love of the Savior with another as a pass/fail test with your grade determined by how your friends respond to your feelings or invitation to meet the missionaries. With our mortal eyes, we cannot judge the effect of our efforts, nor can we establish the timetable. When you share the love of the Savior with another, your grade is always an A+.
Watch the full talk here.
Read what Elder Andersen said about the faith of the people in Africa.