This will give you feels.
"Doctor?" Clara stood behind him, watching him as he piloted the TARDIS, only too quiet.
"Yes, what is it?" She had just only woken up and he wasn't up to answering her questions about his time stream. He didn't enjoy visiting the past, and he had a feeling she wanted to rip open old wounds.
"You lied to me."
"When? I didn't lie to you. Why would I lie to you?" he looked at her for a moment before turning back to the console.
"You told me there was only you in that place. Only you with twelve faces, but you lied. There was someone else. Can you tell me who it was?"
"How can I tell you if I have no idea what you're going on about?"
"The girl, Doctor. Who was the girl with the blonde hair?"
His hands tightened on the knobs he had been screwing with and his mouth fitted itself into a stressed, straight line. "No one, Clara, just someone from my past."
"But, Doctor, she wasn't...real. She was...like a ghost."
He began moving around the TARDIS, trying to run away from the conversation.
"Doctor, who was she? She was even there, with the twelfth man, standing beside him. It was like she could actually see you," Clara ran around the circular room until she met him, face to face.
"What do you want me to say, Clara? I know who you're talking about. I could see her too. But she's just a face in the past. She isn't important."
"See, there you go again, lying to my face. Who is she, Doctor?"
"Rose! Her name is Rose!" the Doctor gave up, slumping against the console, a defeated man. "One of my many secrets."
"Well, tell me this one then, Doctor. No other secret but this. Who is she? I want to know." He smiled. He should have learned by now. When Clara wanted to know something, she wasn't going to give in so easily. He looked up at Clara's lovely face and closed his eyes briefly.
"The only person I have ever loved, and who has loved me back."
"What about your wife?" Clara said, none too gently.
"You want to know, don't you? So don't interrupt!" The Doctor pulled a face and straightened up, turning to her. "I've been left before. They've been torn away, they've left of their own accord, they've been hurt and unable to come back to me, and some...some have died and I haven't been able to save them. Only Rose...only Rose would never leave me. She would never leave me willingly." It was not lost to Clara: there was a far off look in the Doctor's eye; a look of wistful longing.
"What was she to you, Doctor?"
"She was fire. She was truth. She was warmth set ablaze with love and wonder and beautiful longing and intense empathy. She could topple worlds and raise empires with a look. She was quick to welcome you in, but also quick to let you go if you crossed her."
Clara stared at him, catching the wry smile he had on the corner of his lips. "What did she do for you? How did she make you love her?"
"She didn't make me love her. For once, in my nine hundred years, I finally understood what humans meant by 'falling in love.' She saved me." He was quiet for a moment, until Clara prompted him more.
"What do you mean, she saved you?"
"I told you! She was fire and truth and empathy. I met her when I was stone and ice."
"Much like you are now?" Clara gave him a wry smile, but he let her have it. He was lost to the past, old memories flying behind his eyelids, a movie playing in his head that no one else could see. Old victories and falling in love, accompanied by a pink and yellow human, the Bad Wolf who could quell the oncoming storm. Clara had to let him have his moment, or else he might shut down on her completely.
"I met her after the Time War. The last Time War. I had never fully explained this to you, but the last great Time War was the last fight between my people and the Daleks. I had a choice to make. My choice threw me into despair and hatred and I didn't know where to go after. I came back here, a kind of Default I suppose. It was where I'd been when I'd left for the War. Rose was...the first human I met when I came back and I called her a stupid ape...but she still came with me. She still ran away with me. I grabbed her hand and whispered run and she trusted me for no reason at all."
The Doctor was completely lost in his memories now. He didn't know what he was saying, or even that Clara was beside him. To him, Clara was his lost love. His lost Rose.
"I asked her how long she would be with me, and she told me she would never leave me. I allowed myself to believe her words. I allowed myself this little sin because I needed to. I had been alone for so long I forgot what I stood for. I forgot how to do things in the name of the Doctor. I allowed myself to believe she wouldn't ever leave me because I needed someone and that someone had to be Rose. She proved herself time and time again that what she said was completely and utterly true. She was always my Rose." This is where he stopped, the end coming all too soon to his story. He remembered this was not Rose, but Clara, and a new TARDIS room, too new. Too new for his old memories.
"What happened, Doctor?"
"I told you, Clara, she was torn away from me. I pushed her away at first, into a different dimension. I never accounted that she would leave her own flesh and blood for me. She made a dangerous decision and came back for me because she'd always told me she'd never leave me. I believed her then, again. She saved me that day, she saved the entire world, from one of the worst threats the Earth has ever seen. She was torn away from me, though."
"So that's the end of it, then?"
"Not quite, Clara, I told you, she said she'd stay with me forever. She found a way back to me. She found a way through the worlds, dimensions, and universes. She came back to me." The Doctor allowed himself a smile. "But I pushed her away and she had to stay because she had to fix my mistake. That's what it always comes down to, Clara. My friends are always fixing my mistakes," the Doctor's face became a hardened mask.
"That isn't true. We do it because we want to Doctor. You are the single most important man in all of history."
"We don't see eye to eye, Clara."
"Well what do you believe then, Doctor?" Clara shoved her hands on her hips.
The Doctor smiled. "If I believe in one thing, Clara Oswin Oswald, just one thing, I will always believe in her."