Reblogs = inspiration. If you can, we're at the end of "The Crimson Horror". 11 asks Vastra for advice about his feelings for Clara, admitting he has them, but after Rose is afraid to act on them.
“Why are you looking at her like that?” Vastra asked in a low, playful tone that the Doctor was was entirely mistrustful of. Why must she be so perceptive about his life? Why must she notice the kind of things that others were wont to overlook?
“Look at who like what?” he asked, trying to downplay the situation and adopt a jovial, playful tone. “I’m not looking at anyone like anything. What an absurd idea. Why would I be? I don’t look at things. Not ever. I-”
“You’re looking at Clara,” Vastra noted. “Like she’s the centre of the universe. it has been a long time since I last saw an expression like that upon your face, my old friend.”
“She’s… something,” the Doctor admitted, gesturing vaguely with his hands. “She truly is something. A mystery. An enigma. A puzzle.”
“Something more, I feel.”
He sighed. “She’s clever, and she’s funny, and she’s…” he fumbled for the right description. “A match for me. In every sense.”
“So why do you hesitate?”
“After the last time, would you not do the same?”
“Professor Song would have wanted you to be happy.”
“No,” he ran his hand through his hair. “No, not her… I meant Rose. After how that ended… how do I allow myself to love someone of an infinite lifespan? How do I voluntarily submit to that much pain?”
“But how much pain do you endure by keeping her at arm’s length?” Vastra asked with a wise smile, and his shoulders slumped.
“Must you always be so… deep?”
“When you’re as old as I am, you learn some things.”