If I was to ask you how you feel about your father or mother, or your brother or sister, you might say, "That's complicated."
Most people feel ambivalent about many of the people and situations in their lives. Ambivalence in dialogue is always a "Dialogue Deepening Technique." Let's look at one of the ways it can be done. This particular technique is called NPC's "Words are Neither Positive Nor Negative."
Here's the game set-up: You've been driving a tank, and are now getting out of your tank to attack the enemy on foot. With Self Auto-Talk, you ask the gunner in the tank if he'll join you.
GUNNER (wry): Last driver asked me the same thing.
His answer is neither positive nor negative. It reveals ambivalence. Or he could say:
GUNNER: No way. (Pause) On the other hand, I do owe you one.
That technique is called "The NPC is First Negative, and then Positive."
In both examples, because he's ambivalent, we can generate some suspense. You jump from the tank and launch into a fight with the enemy. Will that gunner later appear by your side? Maybe yes, maybe no. With his ambivalent answer, either one is possible.
Here's another Dialogue Deepening Technique:
Let's say that woman we discussed earlier truly is angry at you after you return from fighting the evil deity. She says:
WOMAN (dryly): Weather turned cold while you were away.
The sentence has two meanings: both a literal meaning and an emotional one beneath the surface.
Now, assuming the weather really had turned cold, she'd be talking both about the weather and her feelings about you.