Sentence:  In 1986, she appeared in the stage adaptation of "Les Liaisons Dangereuse" opposite Alan Rickman, playing the manipulative <WSD>marquise</WSD> whose icy demeanour seems to have clung to Duncan's image like frost ever since, even though it is so at odds with her warmth in person. 
Meaning of the word marked with <WSD> tags:  A marchioness, especially one who is French.