He had been told that they were the same person.
I am me, nobody else.
He had been told to ignore everything his heart told him.
My heart belongs to me.
He was told that the person he saw in the mirror was himself, but he knew it wasn't, because he wouldn't fight with himself.
Look which one of us is winning.
He had been told, over and over, that the one he saw in the mirror would fade with time, but he didn't want him to.
You make a good Other.
He had tried to talk to the person he saw in the mirror, but he never received an answer.
Who are you talking to?
He wanted to tell the person in the mirror that he mattered, whether he saw it or not. He wanted to tell the boy in the mirror not to disappear.
No one would miss me.
He tried to force the boy in the mirror to talk to him, but nothing worked, no matter how hard he tried.
I've got nothing to say to you.
He's gone exploring in the depths of his mind, trying to find out what was going on, who the boy was, if anyone else was in there. And he found something.
So you've done a little exploring here on your own, then.
He found bits and pieces, red hair and emerald eyes and ice cream at sunset, as well as tears and seashells and a smile that would never be seen again. And he found himself crying.
You did great. In fact, you deserve a little something extra.
He was told that the boy in the mirror would fade with time, that they would become the same person, and yet…
I have to know.
He wanted to know Roxas first.