Twilight knew Applejack was not okay.
"What's wrong Applejack?" she said to her hat wearing friend "You can tell me anything."
"Ah think ahm immortal." Applejack confessed, tears in her eyes "A knife hit me in the head and the cut just healed itself in two seconds!"
Twilight knew what her friend was talking about because she had experienced something similar when she figured out she was immortal.
"Applejack." she placed her hoof on her friend's hoof, hoping to calm her down "I am too."
There was a moment of silence as the two immortal ponies stared at each other, they were both thinking the same thing.
"I love you AJ," Twilight told her "I never told you because I didn't want to watch you die up close."
The two ponies starting sobbing.
At that same moment, the Appleblooms found Granny Smith dead in her rocking chair.
It turned out in their family they would become immortal once they saved more lives than anypony else in the family, sadly that meant the last family member to be immortal would die a few weeks later.
Rest in peace Granny Smith