What part did Matthew play in Anne's repentance? How did Marilla react to Anne's confession?

Anne is sulking in her room. Mathew creeps upstairs and implores Anne to apologize to Mrs. Rachel. Anne agrees that, for Mathew’s sake, she will apologize to Marilla. Anne's flair for melodrama shines through her apology,

I could never express all my sorrow, no, not if I used up a whole dictionary . . . I’m a dreadfully wicked and ungrateful girl, and I deserve to be punished and cast out by respectable people for ever.

Maarilla isn't impressed by Anne's over dramatic performance.