Samantha Phelps
From Tardis Wiki, the free Doctor Who reference
Samantha Phelps was a human of the 20th century. She was a classmate of Mary Wake.
When Mary told her classmates that she and her family were visited by the Tenth Doctor every Christmas, Samantha made fun of her and bullied by her. However, the Doctor came to Mary's birthday party and Samantha looked inside a magic box that scared her very much. She never told anyone what she had seen in there. However, from then on she believed that the Doctor was real. (PROSE: The Hopes and Fears of All the Years)