Put diced pears into a large stainless steel pan, add pineapple juice and stir to coat pears to prevent them from browning. Add sugar, bring to a boil over medium-high heat. Stir constantly to prevent scorching. When the pears are at a full boil, reduce heat to medium, cook until the mixture is the color and texture of honey. It will get thicker the longer you cook it, (it takes 2-3 hours).
Ladle into hot sterile jars, to within 1/4 inch of the jar rim. De-bubble as needed. Wipe rims with a clean damp cloth, and seal jars with lids and rings to fingertip tight. Process in a boiling water canner with lid on for 20 minutes, remove lid and let it sit in canner for 5 minutes. Remove from canner to towel lined counter to set and cool for 24 hours before storing. Yields 5-6 pints.
Made this two days ago... tastes like honey!