You can pick up this quest by talking with a friendly ghost near the pirate statue overlooking the ocean in Rookridge, close to the Bower Lake entrance. Be sure to pick up the silver key that is located right next to her whilst you are here.
The ghost will ask you to go to Bowerstone Market and seduce a man named Alex. She will also give you an expression book (Seduce) to give you the necessary expression. Travel to Bowerstone, locate Alex and use expressions on him and give him gifts until he falls in love with you. When he does you have a choice between giving Alex the rejection note from the ghost (evil choice) or to marry him (good choice). You will earn +/- 10 morality points depending on your decision.
Either way you decide to complete the task, return to the ghost in Rookridge to complete the quest.