There are many, many ways to know that the Book of Mormon is true—hundreds of ways, I would say. Of course, they all are ultimately grounded in knowing that the Book of Mormon is true through prayer and study.
Isaiah prophesied, in chapter 29, that the Book of Mormon would come forth out of the ground and that it would be a marvelous work and a wonder. Following general rules of English, the King James translators, and maybe Tyndale before them, did not like repetition of the same word. The phrase "a marvelous work and a wonder" sounds better in English than "a miraculous miracle and a miracle." Those who speak English prefer the use of synonyms because we don’t like redundancy. We strive for variation so it does not just sound like we are saying the same thing over and over again. But in many ancient languages, especially in Hebrew, using the same root over and over again was good style. When Lehi stated, "I dreamed a dream," he was using a form that is called "cognate accusative." What else do you dream? You might just say, "I dreamed," and that would get the job done in English. Even though you would flunk English by using such a repetitive phrase today, the idea of repetition was a positive thing in ancient languages. It was considered to be good style.
What was Isaiah really saying in Isaiah 29? Isaiah stated that the record that would come forth was going to be a miraculous work and a miracle. In other words, the book would be a really big miracle—a double miracle—a miracle squared. It was not enough to simply say, "It is going to be amazing." Isaiah wanted to express that it was going to be "miraculously amazing."
As you go through the Book of Mormon this year, I hope you will come to see its amazing qualities in so many different ways. One of the things that makes the book miraculous is that it has so many features and qualities. In the past, I have tried to list some of these. I do not know if you have a list of your own. Many of these words end in "-ity" and some of them end with a "-y." For example, there are things in the Book of Mormon that miraculously manifest its antiquity, and its use of cognate accusatives is one of them. The list of its amazing characteristics is long. This book manifests variety, simplicity, clarity, profundity, sagacity, objectivity, spirituality, practicality, reliability, creativity, maturity, artistry, spontaneity, specificity, generality, beauty, complexity, honesty, subtlety, familarity, accuracy, consistency, legality, authority, universality, reality, and sanctity. I think that’s a really big miracle!
Book of Mormon Central, "Why Did the Book of Mormon Come Forth as a Miracle? (2 Nephi 27:23)," KnoWhy 273 (February 10, 2017).
John A. Tvedtnes, "The Hebrew Background of the Book of Mormon," in Rediscovering the Book of Mormon: Insights You May Have Missed Before, ed. John L. Sorenson and Melvin J. Thorne (Provo, UT: FARMS, 1991), 80–81.