Read the excerpt from act 4, scene 2, of The Tragedy of Julius Caesa r. [ BRUTUS: ] He is not doubted—A word, Lucillius. How he received you let me be resolved. LUCILLIUS: With courtesy and with respect enough, But not with such familiar instances, Nor with such free and friendly conference, As he hath used of old. BRUTUS: Thou hast described A hot friend cooling. Ever note, Lucillius: When love begins to sicken and decay It useth an enforcèd ceremony. There are no tricks in plain and simple faith; But hollow men, like horses hot at hand, Make gallant show and promise of their mettle; But when they should endure the bloody spur, They fall their crests and, like deceitful jades, Sink in the trial. Which central idea is reflected in this passage?