From the introduction in the Book of Mormon:
"We invite all men everywhere to read the Book of Mormon, to ponder in their hearts the message it contains, and then to ask God, the Eternal Father, in the name of Christ if the book is true. Those who pursue this course and ask in faith will gain a testimony of its truth and divinity by the power of the Holy Ghost. (See Moroni 10:3-5).
Those who gain this divine witness from the Holy Spirit will also come to know by the same power
Jesus Christ is the Savior of the world
Joseph Smith is his revelator and prophet in these last days,
The Church of Jesus Christ of Latter-day Saints is the Lord's kingdom once again established on the earth,
preparatory to the second coming of the Messiah."
I testify to you I know these things are true.