"It takes so much more than simple concentration to be able to do this. I don't even know if I would be able to anymore, even." The Doctor was aware that he was babbling in his explanation, and most likely adding extraneous detail. He glanced down at Rose, who was nestled against his side on the sofa in Pete's rec room; Rose lifted her head, compassionate hazel eyes meeting ancient chocolate ones.
"I hope that's not your proposal," Rose whispered, her eyes dancing with humour. "All you ever needed to do was ask, like this: Doctor, will you be my bondmate?" Rose was completely serious, all traces of laughter vanished, replaced by an earnest yearning.
"Life's better with two," the Doctor recalled Rose's words, paraphrasing. "Rose, do you remember our first trip to Platfrom One? The psychic paper read 'The Doctor Plus One'." He slid to the floor, pulling out the ring that his other self had given him on the beach. "Will you be my bondmate, Rose Marion Tyler? My wife, my 'Plus One' as long as we both shall live?"
"Yes, of course. I love you," Rose whispered tenderly.
"I'm going to initiate the engagement bond. I should be Time Lord enough to do this," the Doctor touched Rose's temple and attempted to open his mind. Instantly, pink and golden threads were caressing his mind, threads filled with love and trust. He explored Rose's mind while his fingers became reacquainted with her body. (Reacquaintment became full snogging as the lovers became more mentally intimate.) He would, the Doctor realized, have to teach Rose to put up barriers in her mind. This thought was immediately protested. Rose threw her life's memories at the Doctor. Her first day at school, meeting Mickey, the entire mess that was her two years with Jimmy Stone, working at Henrick's, and finally, the shop exploding.
'Lived everything else with you,' Rose mentally shrugged. 'Don't need any barriers now.' Rose could still feel his uncertainty and she kissed him tenderly, reassuring (after a few failed attempts) touching his mind.