A/N: This takes place as if Rose was never sent to the parallel world in Doomsday. Jackie and Mickey are in the parallel world, so Rose has no one in the original universe except for the Doctor. This is also meant to take place somewhere in the middle of Season 3 probably after 42, but most definitely before Human Nature. Rose and the Doctor have never said "I love you" to each other; however, they have been developing a romantic relationship.
—
Martha woke up in the middle of the night to the sound of music. Getting out of bed and throwing on a bathrobe, Martha leaves her room and follows the sound of the music to the console room. She sees the Doctor and Rose dancing around the console while laughing. They met by the captains chair and dance in each others arms. Still smiling and laughing they dance around the console again. As the song ends they don't stop dancing. After a minute they stop and just stay in each others arms. The Doctor kisses Rose forehead. The Doctor murmurs something that Martha can't hear. She watches as Rose draws back from him enough to look him in the eyes. She doesn't hear what Rose says but the Doctor smiles then kisses her. Martha then decides that's when she should go back to bed, realizing she had just interrupted something intimate.
—
The Doctor was under the console doing work on the TARDIS. Banging at something and muttering words the TARDIS didn't translate. Rose looked down from her book at the Doctor. Willing the TARDIS to make him stop because he had been doing this for the past 3 hours since Martha had gone to bed. The TARDIS hummed in agreement and switches on Moonlight Serenade. Rose gets up from her comfy position on the captain's chair, puts her hand out for the Doctor to see. He mutters something and the TARDIS sends sparks flying at him. He then swears at her in Gallifreyan, jumping.
"Come on Doctor. Dance with me. The world doesn't end 'cause the Doctor dances." Rose says smiling.
The Doctor slides out from under the console, taking off his blue jacket and taking Rose's hand. They start dancing around the console room as the TARDIS hums happily and flashes the lights. They dance goofily laughing and smiling. The TARDIS plays a playlist of Glenn Miller songs along with Moonlight Serenade, like Pennsylvania 6500 and String of Pearls. As the last song ends, they meet again by the captain's seat. Rose wraps her arms around his neck. He pulls her close. They do a clumsy dance in each others arms. They were still giggling at their goofy dance. The Doctor presses a kiss to the top of her head. The song ends and they still are dancing. They stop after a minute.
"Rose?" the Doctor whispers.
"Yeah," she answers quietly.
He draws back a little bit to look down at her.
"Rose Tyler, I love you" he tells her.
Rose smiles and pulls the Doctor to her, kissing him. They pull each other as close as possible. She buries her hands in his hair. Eventually, she pulls away.
"Oh my Doctor, I love you too." she says after a couple seconds.
The Doctor smiles goofily and pulls her in for another kiss.