how is Iago swift arrival expalined in terms of the divine desdemona?

Just as every character has their own manner of speech and expression, Cassio has a very polished, courtly way of speaking, especially of ladies. He describes Desdemona as one who "excels the quirks of blazoning pens"; he calls her "divine Desdemona," but at the same time, wishes Othello much joy of her. Iago's perception of women as deceptive, dominating, and lusty colors the way he portrays both Emilia and Desdemona; both are good women, Desdemona exceedingly so, yet he is able to convince other men that they are anything but what they are.