A method of operating a first user equipment (UE) in a wireless communication system is disclosed. The method includes releasing a first PC5 radio resource control (RRC) connection for which sidelink (SL) radio link failure (RLF) has been declared among a plurality of PC5 RRC connections by the first UE, informing a PC5 unicast link associated with the first RRC connection by a PC5 unicast link identifier (ID) to a vehicle-to-everything (V2X) layer of the first UE by an access stratum (AS) layer of the first UE, and releasing the PC5 unicast link based on the PC5 unicast link ID by the V2X layer of the first UE. The PC5 unicast link ID indicates the PC5 unicast link for which the SL RLF has been declared and the first RRC connection has been released.