Who told Lady Catherine??

Who sent Lady Catherine on her wild ride to Longbourn? I always say that Jane Austen never plants a question in our heads without giving us the answer, and she continues to prove me right.

Emma: in on the secret

“But is it possible that you had no suspicion? — I mean of late. Early, I know, you had none.”
“I never had the smallest, I assure you.”
“That appears quite wonderful.”

“My dear Fanny”

Mary is all, “I’m so glad we’re going to be sisters!” and Fanny writes back, “Thank you for the honour of your note. Here is an icicle.’