Although Henry V of England and Charles VI of France are on opposite sides in this increasingly bloody, bitter conflict, they can still respect each other. Charles shows his respect for Henry and his fighting abilities by ordering his men to fortify French towns against his army. In this regard, the French king's attitude is completely at odds with that of his son, the headstrong and cocky Dauphin, who openly shows his contempt for Henry by sending him a box of tennis balls, which is intended to remind the English king of his dissolute youth.
For his part, Henry shows respect towards Charles after the English have won the Battle of Agincourt and it's time to get down to business and conclude a peace treaty. He calls the King “brother”, an indication of the respect that he has for Charles and his title. Henry then presents Charles with a long list of demands, but invites the French king to confirm, alter, or add to any of the demands as he sees fit.
Of course, Charles, having just lost the Battle of Agincourt, is not in a position to haggle; he has no choice but to accept Henry's terms, which he duly does. But the courteous and polite manner in which Henry presents his list of demands is an indication that he still respects Charles.