Blueblood's thoughts

I have just one question about Princess Cadence. It'll take me a bit to get to it, so I'll beg your indulgence for just a moment.

I have never been anything but honest. I'm Princess Celestia's underhoof, doing what she cannot do so she does not dirty her hooves with our work. I protect her from things Princess Luna and the Royal Guard cannot see, because they will not dirty their eyes with the knowledge required to see them. I study warfare as much as the Guards, and magic as much as Twilight Sparkle.

I have never been anything but what I am, and yet, still you shun me.

Princess Cadence was replaced with a changeling, and you couldn't tell she was replaced.

Somepony, or something, looking like her shows up, calls herself Cadence, and you take her in with open hooves.

You shun me, but embrace her.

Well, my question to you is simple.

She says she is Princess Cadence.

Why do you believe her?