What is love? One defines love in different ways. Cressida is very emotional in Act VI, Scene V of Troilus and Cressida. At line six, she states:
If I could temporize with my affection
Or brew it to a weak and colder palate, 
The like allayment could I give my grief (VI.V.6).

This passage explains the moderation that Pandarus would like instilled on Cressida's emotions, but she feels that her love cannot be adjusted or diluted. Cressida asks her Uncle how she should moderate her feelings, by stating:
The grief is fine, full, perfect that I taste,
And violenteth in a sense as strong
As that which causeth it. How can I moderate it? (IV.V.2-5). 

This is the only time that she addresses her love and it is not directly aimed at Troilus. This implies that Cressida's emotional battle with her appetite for feeling love is not in effect directed towards Troilus. Also present is the fact that she is a Trojan and is being given to the Greeks. This worries her husband, Troilus. His love for her is very simple and true. At line 23, Troilus says, "Cressida, I love thee in so strained a purity that the blest gods, as angry with my fancy- (VI.V.23-24).

Troilus constantly tells Cressida his love for her, but Cressida is not direct with her emotions of love. After Troilus states his love at line 23, Cressida seems to be sarcastic with her response of "Have the gods envy?" (VI.V.27). This remark may not seem to be sarcastic, but Troilus was trying to give his wife a compliment. If Cressida truly loved him, why would she not accept the flattery? The reader gets a sense of foreshadowing into the future of the play by the way Cressida treats Troilus.

As previously stated, Cressida is being given to the Greeks. As a reader of Troilus and Cressida, truth is not what we normally perceive truth to be, but it is rather Troilus asking his wife not to have sex with other men while she is being captive. He is asking her to honor their vows to one another. At line 58, Troilus asks his wife to be truthful to her heart while she is away. He states, "Hear me, my love: be thou but true of heart -." Immediately, Cressida jumps to her own defense and it seems like it is foreshadowing to her being untruthful. Her actions cause her to appear to be suspicious and make the reader question her truthfulness. The play begins to shift when Cressida asks Troilus if he will be true to her, and he responds at line 102: 
[I]t is my vice, my fault, 

Whiles others fish with craft for great opinion,
I with great truth catch mere simplicity (VI.V.102-104).

Troilus is very simple and plain in his truth. He differentiates his truth as a vice of plainness. He is willing to risk his life to see her and his only request is that she remains faithful to him. It does not seem like an unreasonable request considering their married. 
Love and truth are corresponding themes in Act VI, Scene V. Troilus displays his love for Cressida and is constant with the way he expresses his love for her. The love that he has for her is willing to sacrifice his own life.

There is no greater love than when one is willing to die for another. Troilus seems like he will be truthful, faithful to Cressida, whereas Cressida becomes very defensive when Troilus asks her to be truthful to him. There is constancy in Troilus behavior throughout this scene, but Cressida constantly shifts her emotions of love and truthfulness to defense. Her inconsistencies with her emotions in Act VI, Scene V foreshadow the outcome of the play and open the reader to see her consistency to remain true.