In a small saucepan combine water and mint leaves; heat to boiling. Remove from heat and let stand for 5 minutes. Strain, discarding leaves.
In a 4- to 6-quart Dutch oven or kettle combine water and sugar. Heat until sugar dissolves. Skim off top if necessary. Add the mint-flavored water. Keep hot, but do not boil.
Wash, peel, halve and core pears. Place pears in ascorbic acid color-keeper solution. Drain pears; add to syrup. Boil, covered, for 5 minutes.
Pack hot pears into hot, clean pint or quart canning jars, leaving 1/2-inch headspace. Cover with hot syrup, leaving 1/2-inch headspace. Remove air bubbles, wipe jar rims, and adjust lids. Process filled jars in a boiling-water canner for 20 minutes for pints and 25 minutes for quarts. Remove jars from canner; cool on racks.