Whosday: Nine and Rose

Doctor Who has provided many interesting ships throughout its duration, and few draw as many questions as the Ninth Doctor and Rose.

However, there have been clear explanations about it, some throughout the show itself.

Cheem can't comprehend the Doctor and Rose having anything other than a relationship, suggesting that she was a wife, concubine, or prostitute.  From the start of the series, the potential ship is teased.  Not love at all, just unsubtle shipping, but something was intended to be there.

But a kind of chemistry comes into play in the following episodes.  We learn just how defined the Ninth Doctor is be his own pain over the Time War.  Rose is tremendously understanding towards him, despite his sometimes harsh self-expression that can be observed in Dalek.

However, the Ninth Doctor's ultimate demonstration of his love for Rose is his sacrifices to save her life, first risking his own death in the hands of the Daleks by sending her home, and then drawing the energy from her when she became the Bad Wolf, triggering his regeneration.  This reflects the time the Fifth Doctor sacrificed himself to save his companion, Peri.

There's a whole fascinating Tumblr blog that is partly dedicated to specifically this ship, and I'll directly link to the part that focus on 9/Rose.