1- What does Hrothgar claim is the reason for Grendel's mother's attack? What about his explanation, and the language he uses, might be surprising considering he is talking about a supposed monster?

2- How does Beowulf reassure Hrothgar before he dives into the water to
face off against Grendel's mother?

3- How does Unferth participate in Beowulf's quest to fight Grendel's
mother in her underwater lair?

1. She wanted revenge. She had the same emotions as human beings.

2. Unferth gets his reward. Unferth gives Beowulf the sword.

3. Unferth offers Beowulf his own sword, named Hrunting.

Explanation:

1.the hosts on two opposing mountains stood,  

2.thick as the foliage of the waving wood;  

3.between them an extensive valley lay,  

4.o'er which the gleaming armour pour'd the day,  

5.when from the camp of the philistine foes,

6. dreadful to view, a mighty warrior rose; in the dire deeds of bleeding battle skill'd,