Authors Note: This takes place just after S02E10 "Secret of My Excess".
Spike was nervous. He was wondering why Rarity had invited him for tea. She never invited just him for tea. He didn't even like tea. But, any chance to spend time with Rarity, especially alone with her, was welcome.
He was wearing the bow tie she had made for him, and carried a small bunch of flowers. He didn't get very many bits in his stipend, so they were just daisies, not the red roses he wanted to give her. He noticed a few ponies glancing and smiling at him, almost like they were laughing at him. Well, it wouldn't be the first time, so he was kind of used to it.
He made his way the Carousel Boutique, his mind wandering to recent events. He was still embarrassed about the whole dragon rampage 'incident'. Luckily, nopony seemed to make the connection. According the the rumours, the Elements of Harmony stopped an unidentified dragon and banished it to the moon, a volcano, a distant land, and / or the sun. He was happy nopony was connecting the dots.
As he was getting closer to his destination, he remembered how, while he and Rarity were falling to their potential deaths, Rarity stopped him from speaking, and she had tears in her eyes. He could still remember the surprisingly soft hoof, touching his mouth. He could still remember her scent, the perfume she wore, never too much, just right. He still wasn't sure if she was crying from the wind, facing death, or what. He just didn't understand why she did that.
He was finally at Rarity's shop. The sign said it was closed. That was unusual, it was a week day after all. He timidly knocked and waited, keeping his prized flowers behind his back.
Rarity called out, in her delicate voice, "Spike, my little gentlecolt, please come in."
Spike gulped, and let himself in. The sunlight streamed in through the windows, filling the room with beautiful sunshine. There was a small table, elegantly appointed. She had even put a small stool for him so he didn't have to stand to see her. Rarity was siting daintily, with a warm smile on her face. She was wearing the heart shaped fire ruby jewel he had given her.
Spike shyly held the flowers out for her. "T-These are for you, Rarity." He cursed himself for such a poor gift. Rarity deserved only the finest roses, not these farcical weeds.
Rarity's face lit up with delight at the sight of the humble gift. Her horn glowed, and a vase, half full of water, hovered from the kitchen. With equal grace, she took the flowers, placed them in the vase, and off to the side of the table, so it would not black their line of sight.
A silver plate with a lid, bathed in Rarity's horn glow levitated from the kitchen and settled itself in front of Spike. The lid was removed to reveal a plate heaped with gems, all perfectly aged.
Spike stared at the pile and drooled. He couldn't help himself. But, and he was proud of this, he didn't shovel them into his mouth. He glanced up at Rarity, and the gems were instantly forgotten. She glowed in beauty, and knew he could hear a choir of angels singing. He had never been this close to her in such a private setting before.
"Would you like some tea?" Rarity levitated the tea pot, waiting for Spikes answer.
"Yes, please," he managed. The aroma of the herbal tea filled the air, mixing with Rarity's perfume, making the atmosphere even more perfect. Rarity poured herself a cup, took a sip, satisfied the tea was perfect, and smiled at Spike. Spike braced himself then sighed to himslef, 'Here comes the shoot down.'
"Spike, you are a dear friend. A very special friend. Yes, you are young," Spike began to protest, but she held up her hoof, "but dragons mature differently from ponies." She paused, taking a sip of tea. "I shall be completely honest with you. At first, when I meet you, I saw a baby dragon, an adorable child." Again, Spike began to protest. "Please Spike, let me finish. As time has passed, I have seen a maturity well beyond your years, and I have grown truly fond of you. When we had the incident with the Diamond Dogs, I saw a dragon. A dragon ready to risk everything for me. Beyond the bonds of friendship."
Rarity had tears forming in her eyes. She took a sip of tea to compose herself and continued. "That, I think, was the tipping point. The emotions I felt confused me. A full grown mare falling in love with a baby dragon. It was unheard of." She paused for a moment, taking an other sip of tea. "But, it may have been happening. I was so unsure."
"At the Gala, I was desperate to find my price charming. I knew he was by my side the whole time, yet, I thought I could find the same thing with Prince Blueblood, that overgrown snobbish foal. I'm so sorry," she sniffed and blew her nose. "This is not going how I imagined it."
"Then, there was the recent incident. When we were falling to our deaths, I realized I was more frightened of losing you than of dieing." Tears began flowing on her cheeks, "Oh, Spike. I do care for you dearly, but it simply cannot be. You are too young. By the time you're of age, I will be an old mare."
"I don't care Rarity! I'll wait! I'll wait until the universe burns itself to a cinder! I don't care if you're older than Granny Smith, I'll wait for you, I'll always love you." Spike's expression was imploring, begging.
Rarity got up, walked beside Spike, and gave him a tender kiss. "I'm so sorry Spike." Tears cascaded down her cheeks, conflicting emotions burning in her heart.
Spike looked at her for a long time. Finally her said, "I think I understand, but, I will always love you. And the day, no, the minute I have reached the age of majority, I'll be back, my lady. I will be back."