Sentence:  "I'll tell you what we can do," cried her persevering patroness; "we can go as masks, and Lady Juliana shall know nothing about it. That will save the scandal of an open revolt or a tiresome dispute. Half the company will be masked; so, if you keep your own secret, nobody will find it out. Come, what characters shall we choose?" / "That of <WSD>Janus</WSD>, I think, would be the most suitable for me," said Mary. 
Meaning of the word marked with <WSD> tags:  The god of doorways, gates and transitions, and of beginnings and endings, having two faces looking in opposite directions.