Which excerpt indicates that king arthur knows queen guinevere has been unfaithful to their marriage

The answer is "To warn you"

Explanation:

King Arthur is a legendary British leader who, according to medieval histories and novels of chivalry, led Britain's defense against the Saxon invaders in the late 5th and early 6th century. The details of the Arturian stories are mostly composed of folklore and literary inventions, and their historical existence is the subject of scholarly debate among contemporary historians.

The first narrative of Arthur's life is found in the Latin work of Godfrey of Monmouth, Historia Regum Britanniae (History of the Kings of Brittany), completed in 1138. [56] This work is an imaginative account of the kings of Brittany, passing through Brutus to the seventh-century Welsh king Cadwaladr.  Godofredo positions Arthur in the same post-Roman period described by the Historia Brittonum and Annales Cambriae. He incorporates Arthur's father, Uther Pendragon, his wizard adviser Merlin, and the story of Arthur's conception, which Uther disguises from his enemy Gorlois through a magical Merlin, sleeps with Gorlois's wife, Igraine, in the Castle of Tintagel, and she conceives Arthur.

With Uther's death, Arthur, at the age of fifteen, succeeds him as king of Britain and wages a series of battles, similar to those described in Historia Brittonum, culminating in the Battle of Bath. Then he defeats the Picts and Scots, creating the Arturian Empire by conquering Ireland, Iceland and Orkney. After 12 years of peace, Arthur makes new moves to expand his empire once again, taking control of Norway, Denmark and Gaul.  This last one was still part of the Roman Empire when it was conquered, and the victory of Artur ends up leading inevitably to a confrontation with the Roman emperors. Arthur and his warriors, including Caio (Kay), Beduero (Bedivere) and Gualguano (Gauvain), defeat the Roman Emperor Lucius Tiberius in Gaul but, as they prepare to march to Rome, Artur is warned that his nephew Modredo (Mordred) who was in charge of taking care of Brittany during his departure, married his wife Geneva and usurped the throne. Arthur returns to Britain, defeating and killing Modredo on the Cambam river in Cornwall, but is mortally wounded. He passes the crown to Constantine III and is taken to Avalon with the intention of treating his wounds, and is never seen again.

based on the biblical principle proverbs 16: 32, i agree with the author of the passage "better is it that it takes longer to be angry than the strong " to the extent that i share the philosophy that the nobility of heart demonstrates the strength of a person. those who are very proud, get angry easily and show their anger toward others are really weak, but those who are noble and do not constantly obfuscate or contain their feelings of anger, are strong people

heres a link to answer that question enjoy!