Place a rack in upper third of the oven and heat to 450 degrees F. Place 1 sage leaf on a pear slice and secure by wrapping 1 piece prosciutto like a "belt" around the pear. Repeat to make 24 pieces.
Evenly space pears on a baking sheet and place in oven to cook until prosciutto is crisp and pears are slightly softened, about 15 minutes. Serve immediately. Pears can be assembled up to 2 hours ahead. Store covered in the refrigerator until ready to cook.
Pears can also be served uncooked, if desired.
Place prosciutto in freezer for 10 minutes to facilitate slicing.