Book of Mormon translator converted to Church
True/but is often embellished
There are several versions of this story, but the main points are that Elder Russell M. Nelson had a neighbor named Sami Hanna who was not a member, but was asked to translate the Book of Mormon into a different language (the language changes all the time). After translating the book, Hanna investigates the Church and ends up being baptized and joining.
The main points of this story are true. Sami Hanna, who was born in Egypt, was a neighbor to Nelson. He was a scholar with special expertise in Semitic languages. He did translate the Book of Mormon from English into Arabic as a linguistic exercise. Among the many linguistic features that convinced him of the book's divinity was the unusual sentence in Helaman, Ch. 3, v. 14. He said that sentence had 18 ands in it and each and is needed in translating it back into Arabic. He was later baptized. Additional points that are often added to this story are unconfirmed.
Nelson mentions this conversion in a talk called, "A Treasured Testament" in the July, 1993 Ensign.