Am I obligated to guarantee a device that I borrowed from a room endowed by its owners for its use within that room, given that it was stolen a year after I borrowed it, and knowing that the endower was unaware of the borrowing?

If the device was endowed specifically for a particular room, then the borrower is not permitted to remove it from there. This is because such an action is considered an infringement that necessitates compensation. However, if the endowment was general for all university students, then the borrower is not considered an infringer and therefore is not liable if it is damaged or stolen without any negligence on their part.

Based on this, the questioner must compensate for this device, whether it was stolen due to their negligence or not, because they removed it from the room it was endowed for. The compensation should be paid by giving its value to the supervisor of the endowment, or to the endower themselves if there is no supervisor. This value must be used to purchase a replacement for the damaged device, which will then become an endowment as soon as it is purchased.