Daisy is the counterpart to Princess peach just as Luigi is to Mario (though these two aren't sisters). Daisy has always gotten the short end of the stick in the more mainline Mario games, but that's never stopped her from being a superstar in the spinoffs (and Smash Bros will be no exception). Daisy's known for her one famous line "Hi, I'm Daisy" ( https://www.youtube.com/watch?v=s-jKtKJDLJs ), you can either go off of this interpretation of Daisy or come up with your own that you might think fits the character best! She should have the voice of an average young adult, only slightly on the low side, but much lower than that of princess peach.