Here's the walkthrough solution:

23- The Huffington Mystery - (COMPLETE) To initiate this quest, you will need to complete the previous quest “The Missing Jewels”. Talk to Lady Heather about her husband and then talk to the Butler. Afterwards, interact with the study desk in the living room and learn about the ship called the Woodpecker. Now go to the Arbor and ask the Harbor Master about the ship (He is standing behind his desk at the Harbor). He will refuse to help you, choose “Ask Nicely” to get the answers you want. Now, regardless of which path you took with the thief, he will be at the bottom left corner of the harbor, sitting on a box. talk to him and if you chose the good path you can ask him nicely to tell you the location of the Guild of Thieves. If not, you will have to bribe him 2,500 GBs. In any case, if you bribe him 5,000 GBs he will also give you a Brass Key, that he found in the sewers. you can use this key to access a bonus Gate in the sewers. once you have the location of the Guild and the Password to get in, go to the lower right side of the Harbor where you will see a gate. Enter the sewers and make your way to a large Wooden Gate. Give the password “Robin Hoodie” and enter the Guild. to make access to the Guild easier, just climb the metal ladder and unveil a hidden door in the Arbor Town center. Now talk to the Book Keeper which is behind her desk. She won’t help you easily. You will need an Awesome Bow and some patience. Talk to her multiple times about the Huffington Job until you can give her the Awesome bow. After she gives you the information you need, head to the Huffington manor and talk to Lady Heather. Now, go to the Deepthroat Inn at the Arbor at night and enter Lord Huffington’s room. Here you will be given another GOOD or EVIL decision which will not affect future outcomes of the game. Once you have gotten rid of Huffington, go back to Heather and reap the rewards. You can now ask Heather to marry you.