Hi Hela,
It's good to provide examples. Do you mean these kinds of questions?
When / For what purpose do we ask a question in the affirmative form? What difference does it make with the interrogative form?
"You like Tom, don't you?" Here, I'm expecting 'Yes, I do'.
It seems that when we ask a question in the interrogative negative form, we expect a positive answer.
"You don't like Tom, do you?' Here , I'm expecting 'No, I don't like him'.
Best wishes, Clive