What did Mr. Sadler and Marilla discuss?

Mr. Sadler visited Marilla because he was interested in buying Green Gables.

"What did Mr. Sadler want, Marilla?"

Marilla sat down by the window and looked at Anne. There were tears in her eyes in defiance of the oculist's prohibition and her voice broke as she said:

"He heard that I was going to sell Green Gables and he wants to buy it."