What does the quote 'All is fair in love and war'' mean? Do you believe it is true?

Read the excerpt from act v, scene iii of romeo and juliet. juliet: go, get thee hence, for i will not away. [exit friar laurence.] what’s here? a cup, clos’d in my true love’s hand? poison, i see, hath been his timeless end. o churl! drunk all, and left no friendly drop to me after! i will kiss thy lips; haply, some poison yet doth hang on them, to make me die with a restorative. [kisses him.] which tragic flaw of juliet’s character is reflected in this excerpt? a) her optimistic way of seeing the world b) her tendency to act without forethought c) her tendency to act out of vengeance d) her carefree way of living life