Roxane and the duenna return. Roxane and Christian sit outdoors, and Roxane asks Christian to tell her how he loves her. He tries, but all he can say is “I love you,” “I adore you,” “I love you very much,” and other simple variations. Angry, Roxane goes into the house. Cyrano returns, ironically congratulating Christian on his great success.
Seeing a light in Roxane’s window, Christian asks Cyrano for help. In the dark, Cyrano hides underneath Roxane’s balcony while Christian stands in front of it. He throws gravel at Roxane’s window, and when she comes out, Cyrano whispers words for Christian to recite.
Moved by Christian’s words, Roxane then asks why he speaks so haltingly. Impatient, Cyrano thrusts Christian under the balcony and takes his place, still hidden in darkness. Speaking in a low voice, he confides in Roxane the things he has always longed to tell her. As Roxane becomes more and more hypnotized by Cyrano’s poetry, Christian cries out from beneath the balcony that he wants one kiss. At first, Cyrano tries to dissuade him, but he decides that he cannot prevent the inevitable and that, at the very least, he would like to be the one to win the kiss. Thus, Cyrano stands beneath Roxane’s balcony and persuades her to kiss him. Christian climbs up to receive the kiss.
A Capuchin priest enters, having found his way to Roxane’s house. He presents a letter from de Guiche. The letter says that de Guiche has escaped his military service by hiding in a convent. Pretending to read it aloud, Roxane says that de Guiche desires the Capuchin to marry Roxane and Christian on the spot. The Capuchin hesitates, but Roxane pretends to discover a postscript that promises a great deal of money to the convent in exchange. Suddenly, the Capuchin’s reservations evaporate, and he goes inside to marry them.
Cyrano waits outside to prevent de Guiche from disrupting the impromptu wedding.
De Guiche appears. Covering his face with his hat, Cyrano leaps onto de Guiche from a tree. Pretending to be a person who has just fallen from the moon, he distracts de Guiche with an insane speech about his experiences in space. At last he removes his hat, reveals himself as Cyrano, and announces that Roxane and Christian are now married.