We don't know much about the boy. Maybe he was everyone else's last choice. Could be. Not much of a warrior, maybe his parents set him up with this girl, or there'd never have been a marriage at all.
The girl wore some scars from the smallpox that rampaged through her village. Her Huron father and Mohawk mother both died, as did a host of others. The truth? --the girl, Tekakwitha, was forever sickly thereafter. She couldn't have been a doll, but her adoptive father was the village headman.