Clever advertising seduced him into purchasing the expensive watch.

seduced 是动词 seduce 的过去式。seduce 由前缀 se-（表示"分开、偏离"）和词根 ducere（拉丁语，意为"引导"）组成，字面意思是"引导偏离正道"，引申为"引诱、诱惑"的意思。在这里指广告巧妙地诱导他做出了购买决定。