Alma cautions that this is not the end of the process. Faith has been exercised and strengthened, but the individual doesn’t possess a perfect knowledge yet. Note that the 1981 edition of verse 30 contains an additional sentence that was restored from the earliest manuscript of the Book of Mormon:
“And now behold, will not this strengthen your faith? Yea, it will strengthen your faith: for ye will say I know that this is a good seed; for behold it sprouteth and beginneth to grow.”