@Background Pony #D22F  
Way to be depressing…

Applejack would, in my opinion, last the longest of the lot…which would probably be the reason she fell into despair. Seeing all your friends die, one by one, by Soul-corruption (as I like to call it) would be horrible.  
Like with Rarity, I have an idea for Applejack. She probably wouldn’t like to fight the other Magical Fillies, only using violence once she was cornered or it was the only logical thing to do. Even so, I can’t imagine her trying to kill the opponent - she would probably leave enough of a mark to warn them to back off, but not much more than that.  
I imagine her to take the hunts more seriously, not really boasting about them that much. In a way, she would probably be the Mami of the group - more mature and sensible. Also, I think she would take the most time to consider making a contract, unless it was an absolutely desperate situation.  
The truth would mostly likely make Applejack more furious than depressed. I think she would carry on fighting the Witches for a long while, but she wouldn’t feel right doing it. Once all her friends died, she would finally allow her Soul Gem to crack.

This is my favorite of the witch designs so far

@Background Pony #874B  
Failed harvest? Dead family? Foreclosed farm? Apple allergy?

I just can’t imagine what would be enough to throw applejack in despair

“Ingrid Maria”

Well, at least she generate minimal familiars…