This scene in Leonato's garden seems to be a throwaway in that it contains mostly banter between Benedick and Margaret. However, in a play so filled with wit and wordplay, this continues the delightful quality that makes the play so beloved of audiences. At the same time, a darker element is also present, reflecting the way the play itself has become a study not only in romance but also in slander. As a prelude to Othello, the latter part of this play meditates on the power words hold not only to delight but to destroy.
In his soliloquy, Benedick reflects on his inability to rhyme a sonnet in praise of Beatrice and in service to his love. He loves Beatrice yet finds that the fixed form of Elizabethan romantic poetry forces him into false and even ominous language: lady/baby, scorn/horn. Poetic rhyme is all about fulfilling expectations at the level of sound devices, and the play is also about fulfilling social expectations. In this play, Beatrice and Benedick have both chafed at the idea of falling in love, not least because of the false ornament that defines romance in their world.
Later in this scene, Beatrice and Benedick both drop the wordplay that has defined their flirtation. Speaking in simple and honest language about the slander against Hero and the sorrow within her household, they use words to say one thing: "How do you do?/ Very ill."
The opening of this scene prepares us then to recognize that while language can be buoyant and delightful, it can also be harmful. Knowing how and when to use wit and how and when to be honest shows that these two lovers are deserving of the gift of each other's mature love.