A general answer for that is variety and harvest time will determine sweetness. Not sure if you have an Asian Pear or European Pear variety. We typically recommend Asian Pears for South Carolina climates over European varieties due to disease problems.
Here is some growing information on Asian Pears:
Asian Pears should be harvested when skins changes from green to greenish yellow (taste one to be sure) because they ripen on the tree like apples do.
European pears are more difficult to determine proper harvest time. They should be harvested when mature but before fully ripe. Full flavor develops after harvest.
More detail from Virginia Tech: