Handsome Enough to Tempt Him by Laraba Kendig

Forces seek to keep Elizabeth Bennet and Mr. Darcy apart, but hope springs eternal.

Saved from an unwanted marriage, Darcy finds himself in Hertfordshire with his sister and former fiancée. In repayment for a debt of honor, Mr. Darcy assists Bingley in finding a wife who truly loves him by testing his potential brides. Although helpful in some ways, it ends up causing substantial confusion, especially for Elizabeth, who is upset by his peculiar behavior.
Mr. Bennet suffered a terrible injury many years previous that greatly affects him, and his family must endure his poor temperament and sharp tongue. Mrs. Bennet adeptly handles her husband and shields her daughters as best she can.
Darcy quickly finds himself enamored with a lively and lovely woman by the name of Elizabeth Bennet, and she is equally drawn to the noble and intelligent master of Pemberley. Unlike any other woman he has met, Darcy realizes that Elizabeth is, in fact, handsome enough to tempt him.

Over 500 pages. This is a sweet and clean, low angst Pride and Prejudice variation where all of the Bennet sisters have happy endings.