Thanks, Wendy.

Hello Mark, I think in this case, it needs to be either: I have to pay for the car's fuel, after all. or The car's fuel has to be paid for, after all. We're still not sure whether it really is his car, or he's just pretending it might be, in which case the second option might be better?
(otherwise it sounds like he is saying that Stéphane has to pay it.

Test