Berowne enters with Speech #2 praising the pitch-ball eyes of Rosaline. He's got it bad. When he hears the King approaching, he hides in a tree.
The King comes in with an "Ay me," the classic Shakespearean love-groan (4.3.4). Berowne is excitedly watching the King betray his oath with a drippy sonnet about weeping for her love.
But here comes Longaville. The King hops up in a tree and he and Berowne watch the action, commenting without hearing each other. Longaville fears he's not so good at poetry, but nevertheless reads his sonnet aloud. It's all about his vow not to speak to women doesn't matter – because Maria's a goddess.
You just can't guess what happens next. Yes, it's Dumain's turn to enter and profess his love. Now Longaville, the King and Berowne are in trees spying on their lovesick friend. His poem is about wishing he were free as the wind to love her.
Just as Dumain has finished reading his poem out loud, Longaville jumps out of his tree to blame him for loving.
The King hops down to chastise them both. He warns them that Berowne will be merciless when he gets wind of their love. They'll be teased to death.
He doesn't have to wait long to find out, as Berowne jumps down to accuse the King of being in love, too. He has a heyday making fun of them, and lies about his own love.
But here come Jaquenetta and Costard, and you know what they have in their hands (i.e., Berowne's letter to Rosaline).
Costard presents Berowne's letter and calls it treason. The King, unsuspecting, lets Berowne read it. He tears it up.
Longaville sees through Berowne's little tantrum and picks up the scraps of paper.
Now Berowne has to admit it. He'll confess more but wants to get rid of the yokels first.
The boys skirmish about which of their loves is the most beautiful. Rosaline gets kind of trashed by the boys because of her dark hair.
The King calls a truce and asks Berowne how they can justify escaping their vow.
No problem. Berowne gives a long speech, the gist of which is: a) this vow didn't make sense in the first place, and went against all the virtues of youth; b) the best way to learn about beauty (and about how to write) is in a woman's eyes; c) being in love heightens your senses and powers of observation; d) love makes one brave, mysterious and musical. Let's go for it.
The boys need no convincing. They resolve to woo the women, starting with a little entertainment in their tents.