What is the ruling on selling a car for less than its purchase price, given the doubt about swearing an oath by divorce not to sell anything at a loss, and does using the car for a year count as compensation for the loss?

It is apparent from the questioner's current and previous questions that he suffers from excessive obsessive thoughts (waswas) regarding divorce. The cure for this is to completely ignore these obsessive thoughts, cease engaging with them, refrain from asking about them, and earnestly supplicate to Allah for deliverance from them. Attempting to cure obsessive thoughts by pursuing jurisprudential details and loopholes is not a remedy for them. Divorce does not occur due to these obsessive thoughts; for the Prophet, peace and blessings be upon him, said: "Indeed, Allah has pardoned for my Ummah whatever occurs to their innermost selves, as long as they do not act upon it or speak of it." And even if the person suffering from obsessive thoughts utters it with his tongue, his divorce does not occur if it was not intentional, for the Prophet, peace and blessings be upon him, said: "There is no divorce in a state of compulsion/closure."