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Plus, a pretty much unrelated short story about these two!
 
“Wow. Thirteen years since the barn has fallen! Give a round of applause to the safety team!” Applejack hollered at the massive crowd of apples. She walked off the stage and into a small alcove, away from the view of most. “Sugarcube, time for the plan.”
 
“Aye, Aye, Ma!” Sugarcube saluted and ran off.  
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Frost wrung her hooves nervously. It was almost sunset, and no sign of Sugarcube with the signal. “Come on, where is she?” She whispered impatiently.
 
“What was that, Frost?” Saccharine asked, paying vague attention to Rainbow Dash’s haphazard flying spectacle.
 
“Nothing, Love.”  
Finally, her efforts had paid off. Sugarcube trotted over oddly with a huge smile on her face. “Can I steal my cousin for a second?”
 
Saccharine nodded sweetly.
 
“Thanks.” Sugarcube zoomed off with Frost. The two stopped behind the stage, waiting for the sunset to finally start. “Nervous?”
 
“Of course I’m nervous! This is one of the most important days of my life! What if it goes wrong?”
 
Sugarcube rolled her eyes. “How could it go wrong, cuz?”
 
“She could say no! She could walk off, never to speak to me again!”
 
“Careful, Frost, yer stressin’ so much yer mane’s comin’ undone.”  
“Give me a second.” She said after fixing the frazzled earth pony’s band. Moments later, she came back with a brush and directed her cousin to just relax.  
“Okay. Now… you ready?”
 
No. No, she wasn’t. “Yes. I’m ready.” Frost hid the small object under her official Apple family kerchief and prepared to walk onto stage.
 
“And now… Frostbite Apple!” Applejack gestured for the earth pony to make an entrance.
 
“Wow. Look at that sunset.” Frost chuckled awkwardly and took a deep breath. “Look, I know a lot of you don’t like me. I’m not here to tell you that I’ve changed or anything, in fact, I’m not even here for me, so to speak. I’m here for a very special unicorn.” A few murmurs ripples through the crowd. “I know it’s cheesy, but I’m here just to take a minute or two of your time to talk about love.”
 
Sugarcube gave a nod and Frost once again breathed calmer, starting to smile wider and wider. “I first met this amazing pony about two years ago. We were actually enemies, can you believe that? But she helped to show me that my way of thinking was wrong. We were best friends, we went everywhere together. When money got tight, she even let me move in with her. I knew there was more between us than just friendship, but I thought it was one sided, so I waited. I waited for her to confess to me, so I knew that what we had was real.”  
Frost adjusted the microphone and realized she wasn’t nervous at all. She was happy, maybe even excited!  
“But, we all know it’s never that simple. One day, this pony went to the Crystal Empire to browse rare spell books. She slipped and cut herself on a Crystal. Lo and behold, somehow she became evil!” She and the audience chuckled. “I won’t go into detail, I know you’re all just waiting to see who I’m talking about. But.. long story short, a week later, about a year before today, we had our first kiss. It was magical. And… after that whole fiasco at the gala, I think I’m finally ready.”
 
“Saccharine…” Frost knelt down and the crowd turned to the shocked unicorn. Carefully, as the sun set, she pulled the box from its hiding place and opened it, revealing a beautiful gold band and shining amethyst cut in the shape of an apple. “Will you make me the happiest mare in Equestria and be my wife?”
 
Saccharine stood frozen in shock until she suddenly broke down into tears. Teleporting onto the stage, she bawled happily. “Of course! I love you, Frost!”
 
Sugarcube watched with a smirk as the crowd cheered and the new fiancées shared a kiss on the stage.  
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Also.. I have no idea how a pony kneels. But you get the idea.