Nader knows that Razieh is a deeply religious person .
Nader , still wary about the true cause of Razieh 's miscarriage ( and it is likely he does not know about her getting hit by a car ) writes the check and , knowing that Razieh is deeply religious , slyly says he will give it to Hodjat , on the condition that Razieh swears on the Qur'an that his actions were the cause of her miscarriage .
A Separation