When Clara Oswin Oswald jumped into the Doctor's time stream, she became many people. They were always her. Or at least some version of her. They all shared the same name, the same looks. But there was one time when a shade of Clara's looked nothing like her.
Rose Tyler. This shade was made for when the Doctor was at his lowest point. When he needed someone to love him, and accept him, and forgive him the most that was when she was made. And thus, she was born.
Her appearance was not the same as Clara's because that would look too much like the Doctor's recently dead wife. He needed someone similar, but ultimately different. So just this once, Time allowed the shadow to become someone different than the person they were modeled after.
He needed a flower, but someone with thorns, so Rose Tyler was created. She was born to save the Doctor. Every choice she 'made' was to meet the Doctor that fateful day, in that shop.
And she did it. She saved the Doctor. Not only against threats such as the Daleks. But also from himself. If Rose hadn't been there, then the Doctor would have descended in to madness. Into a giant, black pit of despair. She made his life bearable, his pink and yellow human.
She was the only shadow of Clara's to not die for the Doctor. Oh, but she was willing, the Time Vortex, the dimension travels, even the Daleks. She was also the only one to ever get a happy ending. She got the Meta Crisis Doctor, with one heart, and all was well.
That day on the beach, the one when they were returning to their home world, brining the Meta Crisis Doctor with them, something else was said. Just before the Doctor and Donna left, Rose slipped into a trance. Her eyes glowed gold, and she chanted, "Run my clever boy, find our darling daughter, and remember," The Doctor gasped, his eyes widened. Before he could say anything, he ran into the TARDIS, in fear of damaging time.
He couldn't understand of Rose knew those words. How she even knew about Maria at all. 'Maybe when she looked into the vortex, the TARDIS told her,' was the only reasonable explanation he could think of because he hadn't met his Impossible Girl yet. He pushed those thoughts to the back of his mind, trying to convince himself it was a coincidence. He had other problems to deal with. Like Donna.
So, there were never TWO most important women in the universe, according to the Doctor. There was only ONE, since they were technically the Same Person. But the Doctor wouldn't know that for a very long, long time.
A.N. – I don't own anything, just Maria, my Clara is Rose idea, and all my other ideas. The rest of this belongs to Steven Moffat and BBC. Thanks for reading! I would love it if you could leave a review down below!