Answer:
The tone of lines 44-49 is desolate.
Step-by-step explanation:
The desolate attitude of the poet is demonstrated with words like: fearing, mourning and joyless.
This great sadness is caused by the death of his men at the hands of Grendel in Herot and he expresses this act with his words "hate had triumphed", putting Grendel as someone full of hatred who murdered several men.