Why does Beatrice change her name?

Beatrice changes her name to compliment the change in her life. As a Dauntless, she changes her name to Tris, leaving Beatrice the Abegnation behind.

“There’s a reason why she left them, Lauren,” he says. His voice is deep, and it rumbles. “What’s your name?”

“Um…” I don’t know why I hesitate. But “Beatrice” just doesn’t sound right anymore.

“Think about it,” he says, a faint smile curling his lips. “You don’t get to pick again.”

A new place, a new name. I can be remade here. “Tris,” I say firmly.