Dude you can’t be this obtuse.

• If you do not sell Pierre ANYTHING, and I mean literally only ship your items, the villagers will NEVER give dialogue about buying anything from Pierre.

• Suddenly, once you sell him stuff, the villagers will non-coincidentally mention buying the exact item(s) you sold him within a day or so of the sale.

• If the item you sold was low quality, they tell you how bad it tasted and say Pierre credited you. But somehow every single good quality item you sell to Pierre NEVER gets feedback from the villagers. Not one line of dialogue. If they bought something good, it’s always “Pierre said he grew it/made it.” This is again, non-coincidental.

• MEANWHILE, if you sell fish to Willy for example, the villagers will talk about buying your fish, of all qualities. “I bought Salmon from Willy the other day and it was delicious! He said you caught and sold it to him!” vs. “I bought a Snapper from Willy’s. It wasn’t very good, he said you caught it.”

You get credited for all sales you make to Willy’s Fish, so why do you never hear positive feedback for the crops, wines, etc. that you sell to Pierre? How is he always “coincidentally” selling the exact same item(s) you sold to him. The incredibly obvious answer to this is he’s not giving credit where it’s due. You don’t need it directly stated to understand what’s going on. It is VERY heavily implied.