An embodiment is a method for operating a relay User Equipment (UE) in a wireless communication system, the method comprising steps for the relay UE to: measure the link quality between a source UE and the relay UE; and receive information related to the link quality between the relay UE and a remote UE from the remote UE, wherein, when the relay UE does not know the Quality of Service (QoS) required for a message, resource reselection is performed on the basis of the difference between the link quality between the source UE and the relay UE and the link quality between the relay UE and the remote UE being greater than a preset value.