Your business associate has one more proposal for you.
Your main mission NPC suggests that you strike out on your own from now on. To help you with that he is introducing you to a business associate of his. However, for that associate to agree to work together with you, you will in turn have to convince her three partners first.
This is a three part mission. To speed things up, it might be advisable to take the following items with you before going to see your new partner:
The first NPC you have to convince will want three different stacks of items as a sign that you can deliver on your promises (list see above). After you've provided these, you will have to set sail to the next port.
The second NPC wants you to help him with a trader that is slandering him and telling everyone he's cheated. Convince that man that silence is better for his health. What this comes down to is a swashbuckling duel with a single level 24 Lieutenant. You will only have to bring him to about 25% health before he'll surrender.
The third NPC will just expect you to answer a question or two. Since you only get one reply option in each case, there's nothing you can do wrong here. Finish that conversation, then return to talk to your new partner, THEN return to the first port to finish the mission and claim your reward.