What is the Sharia ruling on a driving instructor paying a bribe on behalf of a trainee, without the trainee's knowledge, to guarantee their success in the exam? And is it permissible for the trainee to return the money to the instructor who paid the bribe, given their feeling of guilt?

Bribery is one of the major sins, and its perpetrator is cursed by the Messenger of Allah, peace and blessings be upon him, who said: "The Messenger of Allah, peace and blessings be upon him, cursed the one who gives bribes and the one who takes them." You bear no sin for the bribe that occurred, as the sin lies with the one who paid the bribe and the one who took it, for Allah Almighty says: "And no bearer of burdens will bear the burden of another." The trainer has no right over you, and you owe him nothing. The one who must return what was paid is the one who took the bribe, and the trainer should be advised to repent to Allah for what he has done.