The want is what your character consciously chases; the need is the deeper truth they must accept to actually grow.
In storytelling, a character's want is their conscious, external goal - the thing they're actively pursuing throughout the plot. Their need is something internal they must learn, accept, or change about themselves, often without realizing it. The tension between these two creates the emotional engine of your story. When want and need finally collide, that's where the most powerful character moments happen.
If your character only has a want, your story is just a checklist of plot events. If they only have a need, there's nothing pulling the reader through the narrative. The magic is in the gap between the two. That gap is what makes readers feel something when the character finally gets what they need - or tragically doesn't.
Gatsby wants Daisy Buchanan. What he needs is to accept that the past can't be recreated - but he never does, and it destroys him.
Woody wants to be Andy's favorite toy. He needs to learn that love isn't a competition and that sharing it doesn't diminish it.
Katniss wants to survive the Games and protect her family. She needs to recognize her power as a symbol and accept the responsibility that comes with it.
Fleabag wants connection (especially romantic), but what she needs is to stop punishing herself for her role in her best friend's death.
Create separation between them. The want should be tangible and external; the need should be emotional and internal.
The need should click into focus at or near the climax. If they figure it out in act one, the story loses its tension.
Don't just tell us the character needs to 'learn to trust.' Show them in situations where trust is tested and they fail - until they don't.
Write two short paragraphs about your protagonist. In the first, have them explain what they want in their own words - what are they chasing and why? In the second, write what they need from an omniscient perspective - what truth are they avoiding? Then write one sentence describing the moment where these two collide.