Is Jesus the Christ?

Do believers ever doubt Christ? If so, why? How does our Lord show tenderness even with John the Baptists question as to whether Jesus was the Christ? How did our Lord turn John's question into a teaching opportunity to speak of John's mission as the forerunner, but also as a condemnation of the religious leaders who, in spite of the clear proofs of the Lord Jesus being the Messiah, they continued to reject him?