What are three types of deception in Twelfth Night?
Three deceptions are Viola’s posing as Cesario, Maria’s letter to Malvolio, and the duel.
Clearly the most glaring deception in the play is Viola pretending to be a man. She decides she wants to intervene in the situation between Olivia and Orsino, and ends up as a member of Orsino’s court. He confides in her and comes to respect her, but the whole time he has no idea who she really is.
Things get even more complicated when Orsino sends “Cesario” to make his case to Olivia that she should not pine for her brother. Olivia then falls in love with Cesario! Viola does not know what to do, because she was supposed to be getting Orsino and Olivia together. She seems to be the wrench in the plans.
Viola is somewhat impressed by how effectively she has convinced everyone she is a man, but she also feels bad about what she has done. After all, Olivia has no idea who she really is. Her deceit of Orsino, whom she loves, is bad enough. She has deceived Olivia too. Olivia has switched from pining for her brother to pining for Cesario, who can never return her affections.
What will become of this? As I am man,
My state is desperate for my master's love;
As I am woman,--now alas the day!--
What thriftless sighs shall poor Olivia breathe!
O time! thou must untangle this, not I;
It is too hard a knot for me to untie! (Act 2, Scene 2)
Poor Olivia! Viola just does not know what to do. She did not mean to hurt anyone when she entered into the duke’s service. Yet she has created a situation that seems hopelessly complicated.
Another deception also involves love, but this one's malice is intentional. The lords and servants of Olivia’s house seem particularly close, except for Malvolio. He is the odd man out. Tired of his chiding, Maria and Sir Toby decide to play a trick on Malvolio. They convince him that Olivia is in love with him by writing a letter, supposedly in her handwriting.
… If thou
entertainest my love, let it appear in thy smiling;
thy smiles become thee well; therefore in my
presence still smile, dear my sweet, I prithee.'
Jove, I thank thee: I will smile; I will do
everything that thou wilt have me. (Act 2, Scene 5)
The trick played on Malvolio is nothing short of cruel. He may be pedantic and prudish, but he did not deserve to be so mistreated. It is not enough for them to give him the letter so that he makes a fool of himself with Olivia. They also convince her that he is mad so he can be locked away, and then use Feste to harass him by making him think he is talking to a priest.
The servant-lord entourage is up to other tricks when they convince Sir Andrew and Cesario to duel. Neither of them want to. Sir Andrew is a coward, and Cesario is a woman! Yet Sir Toby and Fabian convince each that the other is an audacious fighter, and they must fight for Olivia’s affections.
Why, then, build me thy fortunes upon the basis of
valour. Challenge me the count's youth to fight
with him; hurt him in eleven places: my niece shall
take note of it; and assure thyself, there is no
love-broker in the world can more prevail in man's
commendation with woman than report of valour.
This causes more trouble than they could ever imagine when Antonio shows up thinking that Viola/Cesario is Sebastian! The duel ends up with Sebastian the one fighting Sir Andrew, and things just go downhill from there. Sebastian is nothing like Viola. He is pretty much ready to fight anywhere.
This is about the time when the game is up. Eventually they figure out that there are two of them! By that time, Sebastian has married an unwitting Olivia, who thinks she is marrying Cesario. Antonio has been arrested, with Sebastian not there to help him. He gave his purse to Sebastian, but tries to get it from Cesario. Viola’s deception wreaks havoc!
Most of the deception in the play is intended to be harmless. Viola certainly never meant to hurt anyone by pretending to be Cesario. Maria and company just thought they would have a little fun with Malvolia, and Sir Toby was just enjoying himself when he spurred Sir Andrew into a duel. All of the deception, whether for fun or intending to help someone, ended up with unintended consequences.