Once converted the Lamanites never strayed from the truth

Alma 23:6 And as sure as the Lord liveth, so sure as many as believed, or as many as were brought to the knowledge of the truth, through the preaching of Ammon and his brethren, according to the spirit of revelation and of prophecy, and the power of God working miracles in them—yea, I say unto you, as the Lord liveth, as many of the Lamanites as believed in their preaching, and were converted unto the Lord, never did fall away.