Possible Clues:

• Whence the phrase 'wear one's heart on one's sleeve'
• Shakespeare play turned into a 12 by Verdi
• Disc-flipping game
• Loves to involve the two learners in play
• Books with greeting in Shakespeare play
• Turned to welcome Shakespearean character
• The lord in 'O, beware, my lord, of jealousy!'
• The lord in "O, beware, my lord, of jealousy!"
• 'Sweet revenge grows harsh' speaker
• Source of the words 'O, beware, my lord, of jealousy; / It is the green-ey'd monster ...'