Qu Fulan did not meet with the merchants personally. It wasn't that she thought too highly of herself; it was inconvenient to reveal her identity. Otherwise, once they collaborated, people might misuse the status of Young Lady Pei, which wouldn't be good.
So, she selected a shopkeeper to deal with the merchants on her behalf, following her instructions to negotiate business, while she listened from the next room.
Qu Fulan's plan wasn't complicated. The underwear business couldn't be monopolized. Since the business would be divided sooner or later, why not bring others in to collaborate?
The supply and prices could be negotiated.
The underwear market is vast; one person can't consume it all. Now, she's taking orders from nobles to maintain her clientele in this regard, other clientele she cannot currently cater to, so these merchants can consolidate it, take goods from her, reach a cooperative agreement, and achieve mutual benefits.
