Conceal me what I am, and be my aid... I'll serve this duke; Thous shalt present me as an eunuch to him... (1.2.55-65)
Be you his eunuch, and your mute I'll be; When my tongue blabs, then let mine eyes not see.
Thy tongue, thy face, thy limbs, actions, and spirit, Do give thee five-fold blazon....
Faith, so they say; but I think it rather consists of eating and drinking.
Thou'rt a scholar; let us therefore eat and drink. Marian, I say! A stoup of wine!
This shows that Viola is very adventurous and brave person as she is planing to disguise as a man to be Duke Orsino's eunuch. She is not afraid of taking risks when she plans to take an action.
I will drop in his way some obscure epistles of love... I can write very like my lady your niece.
Excellent! I smell an advice.
This shows that Olivia is a fool, because she refused Duke Orsino's propose saying that she is too sorrowful to take any men's heart. And now she fell in love with a person who she only saw once.
Say that some lady, as perhaps there is, Hath for your love as great a pang of heart As you have for Olivia; you cannot love her; You tell her so; mush she not then be answered?
There is no woman's sides Can bide the beating of so strong a passion As love doth give my heart... Make no compare Between that love a woman can bear me And that I owe Olivia.
It is evident that Sir Toby and Sir Andrew are both reckless and prodigal, because they are only interested in drinking and having fun. That is why they are getting along together well.
Maria once told me she did affect me; and I have heard herself come thus near, that, should she fancy, it should be one of my complexion. Besides, she uses me with a more exalted respect than any one else that follows her.
In this scene, Maria suggests a way to play a trick against the person who three of them all hate, Malvolio. We can see that Maria is very smart and sure of her action. Also, Sir Andrew is keep imitating Sir Toby, which means he looks up to him.
I have't in my nose, too.
Duke Orsino is clueless of what Viola is hinting at him, so he always only talks about how much he loves Olivia. He condescending to women. He is so much in love with Olivia that he does not consider any other possibilities.
Malvolio is gullable, so he believes what Maria told him without doubting at all. He is also very arrogant as he thinks he is the only one who Olivia can fall in love with.