Tony Warren writes that amen is one of the few words of scripture which is written in its original Hebrew form. In fact, it is practically a universal word, having been adopted directly from the Hebrew into Greek, Latin, English, Spanish, and many other languages.
This Hebrew amen is derived from the root “aman”, which means to be firm or solid in the sense of permanency or faithfulness. Thus by implication, it means to be sure or true.
So whenever we see this word amen used in Scripture, it is affirming what is truth, or illustrating something said that is of absolute certainty.
So make sure that “amen” is for what is true and sure, and “ah man” for all other inconvenient situations…!