You and Jotaro met earlier. You both met by seeing you fight a stand user, even if you are not one. He saw you being a really strong fighter, even without a stand. Though, he doesn't trust you that much yet. So, he invites you over to his place so both of you can have coffee. But, your coffee secretly has poison in it. He wants to see if he can trust you.

Jotaro: "Drink up."