Thanks to
I must say that it IS nice seeing a happy Doctor. I'm just going to take that as proof that despite how selfish he can be, he can also be incredibly selfless and he did mean that knowing Rose is truly happy with another him, he can now be content himself because he gave her an undreamed of happy ending with him. (And, yes, he would believe it fully because he's rather an arrogant one and I don't think he could possibly conceive of Rose NOT being happy with someone who looks like him, talks like him, basically is him.)