How can we know if the Bible's promise of everlasting life is true? One word: prophecy. One prophecy (among many) says that troubled times would come, with "men's hearts failing them from fear and the expectation of those things which are coming on the earth." These certainly are troubled times. The CDC reported that in June 2020, a massive 25 million Americans seriously considered committing suicide.
However, among its fearful predictions, the Bible also gives wonderful hope to those who will listen. Only God knows the future, and thanks to the Scriptures, so can we.