Compare and contrast characters based on their actions, traits, and motives. So here's my point: Just compare and contrast Katniss and Peeta to Gale and Peeeta.

Katniss and Peeta have a surface level motive, to win the Hunger Games. However underneath this, Peeta's actions such as joining the careers are really because he's in love with Katniss; this is why he wants to win the Hunger Games. One of Katniss's strongest traits is that she is a compassionate older sister. This is her motive for winning the Games, she wants to provide for her family. Her actions support this as she is shown to take care of Rue, who reminds her of her sister. Katniss has straightfoward motives, where Peeta's motives are a little harder to straighten out. Although they show it differently they are both motivated by love.

Gale and Peeta are also both motivated for their love for Katniss. In the first book Gale wants katniss to run away with him when he is almost certainly going to have to go into the Games, but then when he is out of the reaping in the second book he no longer wants to run away with Katniss. He loves her, but values himself more so. And the you have Peeta, he not only volunteers for the 75th annual Hunger Games to protect Katniss, but he puts himself in harms way over ad over again in the games to try to keep her alive. Where both men are in love with Katniss, Gale does so selfishly while Peeta is selfless.