“不忍用杖” can be translated into English as "reluctant to use the rod" or "hesitant to wield the cane", depending on the context and the specific imagery you want to convey.
"Reluctant to use the rod" implies a hesitancy or unwillingness to apply strict discipline or punishment.
"Hesitant to wield the cane" carries a similar meaning but with a more literal or physical connotation, often associated with corporal punishment.
Choose the phrase that best fits your intended meaning and context.