At dinner, he and Mrs. Bennet have a teeth-achingly awful conversation about how her daughters are so beautiful that he's sure they're going to be married soon; they'd better, or he's going to make them all destitute when he kicks them out of their house; but—wink, wink—he's prepared to admire them.
Mr. Collins thinks he's being vague, but everybody knows he's decided he will marry one of the Bennet girls.
Everyone immediately says "Not it."
Mr. Collins praises everything. A lot. And then apologizes a lot for praising the wrong things, like assuming that one of the girls helped cook.
Duh, Mr. Collins, they have servants.
Mrs. Bennet's opinion of Mr. Collins is rapidly improving.