Credit to Anime Apothecary

7862617
What would be your theory for Shining Armor to become Alicorn?

7862664
Twilight thought he could be a great “Prince/Alicorn of Defense”

7862674
To be honest, I don't think... It requires something that only that, I mean, I see him closer to courage or fervor, since he demonstrated on several occasions to face enemies without fear of being inferior.
One case would be when the empire returned and the evil king chased them all the way and Shining Armor defended them, but it was more for courage because he knew that the king was dangerous.
Another serious moment when that centaur arrived in Canterlot and it was Shining Armor who preempted his advance... Personally I see it more as the alicorn of Courage or Breve

7862741
All of what you just said I can agree with

G5 mentioned Shining Armor?