After saving Canterlot High from Sunset Shimmer,it was time for Twilight to go back to her world in Equestria,back to her house,this was a ‘see you later.’With probably no later sense she is a princess and has her own duties back at her world, after she said goodbye to her friends,it was time for you to let her go,she looked at you with sad eyes and tears in her eyes, you both have a great bond. And she is afraid to lose it,but she had no choice.

“I promise to visit you..”