I shall not disparage destiny, because I have always had little else to believe in, but my heart is still filled with doubt. Even as I watch you leave me for the first time, I cannot be proud. I feel nothing like the page’s mother sending away her only colt with dreams he will become a knight. I do not think this because I know the cheapness of dreams, but because without you, Twilight Sparkle, I have little to look forward to.

I have always had a desperate need of you, one I have never been able to bring myself to show. My need of you has been greater than the need for anypony else in my eternity, though I would never blatantly put that pressure on you. How could I say such a thing? That, I, the goddess have a greater need for you than you did for me when you were a filly? There are many fears that crawl up my throat so desperately as I watch your chariot depart, and I could not bear to voice any of them. Goodness me, I am burdened by the mere thought of all this emotion, and it weighs upon me more than crowns and chariots.

Is it any wonder I have always envied the statues in my garden?

Here I stand, in the city, I have built for another, and the nastiness of powerlessness is upon me. I don’t want to watch you go because I have never wanted you to leave me, but I always knew I would have to make you do this. Such is destiny. Such is fate. I have always said that destiny, and dear life itself, never let bad things happen to good creatures. Only those who are wicked will ever find even the smallest amount of wickedness come back to them. And is destiny not the harmony I want you to discover for yourself?

The thing that pains me the most about your great destiny, Twilight Sparkle, is that I cannot orchestrate every step of it myself. You cannot comprehend how dearly I want to pluck every string in the symphony of your life, to give you reward beyond measure, and heroism without risk. Instead, I find myself idle and unable to lift hoof or horn to help you.

Even if I could, how could I help you against that which I could never face myself?

Who I could not face myself. The same who I have always had to stare down and say was a storybook legend instead of my own sister. The same sister who you have spoken of as an utter monster and breezie tale paragon of evil for as long as you have lived, as have all my other Faithful Students. You do not remember all your foalhood naivete and first stumbling steps to analyze the breezie tales that never made enough ‘sense’.

But I do. You played the little professor, which I am sure is something within your destiny. Your mother’s spare pair of reading glasses was your uniform. Oh my, I think you have been the only little foal to ever say to me that breezie tales should only serve as strict moral guidance, otherwise they lacked any purpose that rationalized why they deviated from reality.

Worse than you leaving is the doubt that plagues me. I feel that it is an infection, but not the kind that a mare could approach a physician about. That would be a confession, and there is nothing that I am against more than confession. Even the idea of it is something that is deeply troubling to me. I should not doubt that you are the hero I made you to be. My mind is a torturous, rebellious thing, however, and it seems that it wants for nothing else.

I have never had a foal, nor have I ever considered myself a mother. Yet, the sacrifice I have made in parting with you brings to mind all the empty nest tales I have been told for eras. Loss is horribly familiar to me, but never before did I think I would understand anything of what mothers may go through. It has always been something that I’ve considered to be unrelatable. My students are my treasures as the craftspony cherishes every chess piece they’ve carved. I know that I have made you, Twilight Sparkle, but I have not made you in the way your mother has. Kindness is kindness to me, and I can’t see any reason to put the love of a mother and a teacher in the same box.

Every wingbeat of my pegasus guards takes you farther away for me, and the only optimism I had is that I had not poured all this awfulness over you. That I am letting you be a hero, and a hero like no other as well. None of my past Faithful Students made it to where you are, but none were destined to be my Spark, the Spark.

I could not make them into somepony that would work, even if they had your cutie mark, and your pure soul to boot. None were my Sparks, even if they ended up heroes. It only hurts me more to see that the one Faithful Student - and I mean truly faithful - that I have had is the Spark I must cast from the fire, and see if you survive. You were never the one that I could bear to gamble with, Twilight, just the one I had to.

With each pace that puts you closer to Ponyville, I am left here among the spires of Canterlot. I want nothing more than to take ten paces for every one my soldiers make to bring you back, under my wing, where you will not have to leave again. I’m afraid it has been a long time since I have gotten anything I have wanted.

And now that you are gone, I am left with only my horrible words.

Even Grammarly agrees that the tone of this is best described as 'disheartening'. Find the short version here.