Anne saw it. In fact, she picked it up and played with it, even though she wasn't supposed to. Which makes her, in Marilla's eyes, the guilty party.
Which Anne steadfastly denies.
"I never took the brooch out of your room and that is the truth, if I was to be led to the block for it—although I'm not very certain what a block is. So there, Marilla."Result: Anne is confined to her bedroom until she confesses -- which means, if she doesn't, missing the Sunday School picnic. (Again, Chapter 13.) Which means she's in the depths of despair -- oh, and refusing
"Boiled pork and greens are so unromantic when one is in affliction."Matthew, incidentally, is the person who listens to this particular plaint, which sticks with him when he goes down to his own dinner:
"mournfully surveying his plateful of unromantic pork and greens as if he, like Anne, thought it a food unsuited to crises of feeling"Marilla has her doubts, but she's not willing to share them. She reminds Matthew that the whole child-raising thing is her business, thank you very much.
"The retort silenced Matthew if it did not convince him. That dinner was a very dismal meal. The only cheerful thing about it was Jerry Buote, the hired boy, and Marilla resented his cheerfulness as a personal insult."Result: Since she's not allowed out of her room until she confesses, and she desperately wants to go to the picnic, Anne decides to make up an elaborate confession, the upshot of which is dropping the brooch into the pond during a romantic reverie.
Which, understandably, displeases Marilla. As punishment, Anne's not allowed to go to the picnic after all, prompting moans of unfairness.
Until Marilla discovers that the brooch has, in fact, gotten caught in her shawl, and has been hiding in the closet for the past two days. Much apologizing ensues, Anne goes to the picnic, and all is well again.