What does Genesis 24:8 mean?

In the previous verse, Abraham expressed confidence that God would make a crucial mission successful. The servant Abraham is sending is meant to find a wife for Abraham's son, Isaac, among Abraham's people in Mesopotamia. An angel of the Lord would go before his servant to ensure that a suitable wife would be found for Isaac among Abraham's people, a woman willing to move from her family and live in the land of Canaan.

Now, though, Abraham assures his servant that if he's wrong, if the woman is not willing to return to Canaan, then the servant will be released from the oath. The most important thing is that his servant not take Isaac out of Canaan under any circumstances. Did Abraham make this concession because he suddenly doubted God would provide? Probably not. More likely is that Abraham wanted to reassure his servant. This would make it easier for the man to swear to take on this mission without himself having to be confident that God would supernaturally intervene.