Question

Which lines in this excerpt from act V of Romeo and Juliet show that Romeo feels guilty about having killed Juliet’s cousin Tybalt?

Answer 1

After Tybalt's death, Romeo recriminates himself:

This gentleman, the Prince's near ally,My very friend, hath got his mortal hurtIn my behalf; my reputation stain'dWith Tybalt's slander.--Tybalt, that an hourHath been my cousin!  O sweet Juliet,Thy beauty hath made me effeminateAnd in my temper soften'd valour's steel! (3.1. 1.109-115)

Romeo is ashamed that he has been weakened in his "valour" and integrity.  Heretofore, he has been known for having been a rational and honourable man.  But, in his "effeminancy" [weakness, powerlessness] he has become emotional and acted tempestuously.