The opening scene of this famous comedy, as is evident from its very first few lines, is characterised by relief, joy and jubilation. This is because Don Pedro, the Prince of Aragon, has just been victorious in a battle and has lost very few men in gaining that victory. Note what the messenger replies to Leonato when asked about the number of men killed during the battle:

But few of any sort, and none of name.

Leonato responds that a victory is much more significant when the victor is able to bring home full numbers. The news that he and his men will stay in Messina with Leonato is something that would have been greeted with joy, as the arrival of the young lords, fresh from their victory in battle, would have been something that the young unmarried ladies would have eagerly anticipated. This is something that can be seen clearly in the Kenneth Brannagh film version of the play, where the news that the soldiers are returning throws all of the women into a frenzy of excitment as they rush around and get ready to greet the returning soldiers. The tone in this opening scene is therefore one of joy and jubilation.