Matt Smith (as we can all tell) is more forward then the previous two Doctors. Whether it come to being more violent, more arrogant, or more romantic, he isn't as shy or afraid of losing things as the previous actors seemed. Because Clara is on her 3rd life (that he's aware of) he is more intrigued by her, and I think he has a spark of hope that because she has been reincarnated multiple times, that his 'living forever' wouldn't be a problem in their connection as she'll also (in a sense) live forever.
Yes. More even I think. I've never been a fan of River Song and I think she'll die in 'the nam of the doctor', opening a path for a Clara- Doctor relationship, and I sincerely think that would be the cutest thing ever. For a moment hell have the illusion that she can live forever with him and then bang! She dies and he's left there, lonelier than ever, with a bigger hole in his heart than ever before.
Yeah not a really cheerful picture I realise but that's what I think.
