Trevor Noah was surprised by his mother's choice to stay in South Africa because during apartheid, the government enforced a system of racial segregation and discrimination that made life extremely difficult and dangerous for black people in South Africa.
Noah's mother, who is black, had faced significant challenges and discrimination throughout her life, including being jailed for being in a relationship with Noah's white father.
Given these experiences, Noah expected that his mother would want to leave South Africa as soon as possible. However, to his surprise, his mother chose to stay in the country even after the end of apartheid, as she felt a strong sense of attachment to her home and community.