What is the real meaning of the use of the word “Amen”? I’ve heard that it “Amen” has more of a serious meaning than just the common translation of “So Be It”.

Adapted from The Power of One Word at Torah.org:

The commentators explain that the word Amen is related to the word Emunah – Faith. The person who makes a blessing over a delicious fruit, for instance, is poised to enjoy this wonderful pleasure, and naturally, he expresses his gratitude to the Creator of all things. A person who makes a blessing under other circumstances, such as the performance of a Mitzvah, expresses an intellectual appreciation for the capacity of a Mitzvah to reinforce the relationship between a human being and his Creator.

The one who answers “Amen” however, is not acknowledging the bounty of the Creator out of gratitude, nor is he communicating his appreciation on an intellectual level. Rather, he is grasping the occasions that warrant blessing to express himself to [G-d] in terms of a pure faith unrestricted by the limits of his gratitude or the boundaries of his intellect. His connection with the Almighty transcends the human condition entirely and derives directly from the absolute spirituality of the divine spark in the human soul. It is a total sublimation of the self in the Infinite. This connection as expressed by the single word Amen, explains the Talmud, is far greater than the blessing itself.