The inference that best supports the passage is "Beowulf is stronger and braver than the average warrior".
Step-by-step explanation: Beowulf is certainly not the average warrior - he survived his swimming contest in Breca, and killed many sea monsters. He explains he was able to accomplish those impressive feats because "fate spares the man it has not already marked". This means that if your fate hasn't already been determined, anything is possible through sheer courage and willpower.