Answer:
“Thou hast described a hot friend cooling”
“When love begins to sicken and decay/It useth an enforcèd ceremony”
“But hollow men, like horses hot at hand/Make gallant show and promise of their mettle”
Step-by-step explanation:
The line "Thou hast described a hot friend cooling" supports the conclusion that Brutus and Cassius are in conflict because the description of the friend being "hot" means that the friend is angry. Brutus is saying that Lucillius is describing Cassius as being angry but at least calm. The line that begins "When love begins to sicken" is also indicative of the conflict. Brutus is describing the love that the two friends had a dissolving and now Cassius is simply doing what would be considered polite and courteous rather than the warm greetings or actions of a close friend. The last line uses a simile to compare horses to men to show how when they are in conflict or unsure around another like to boast and show off their strength. This is almost a way of measuring up to the other person.