I am not sure which part you are talking about. There are 2 possible parts:
the first part:
You could be talking about the girl in the tree; Rue. She helped her because she realized that she was a good person.
The second part:
You could be talking about the guy; Thresh, that saved her when the girl; Clove, was trying to kill her with a knife. He saved her because she helped Rue (Rue was in the same district as him); and you could have 2 people win if they are from the same district.
In the first book, Peeta saves her by teaming up with the career tributes to protect her because he is in love with her. Rue also saves Katniss by pointing out the tracker jacker nest that she can release onto the career tributes to stop them killing her. Later in the book, Thresh saves Katniss by pulling Clove off her and crushing her skull to stop her killing Katniss. Once more, Peeta stops Cato, in the fight at the end, from harming Katniss. Mainly Peeta saves her because he is willing to do anything to protect her.
When her sister Primrose got chosen during the reaping, Katniss volunteered to be a tribute. To save Prim's life.
Because She was allies with rue and she covered her with flowers and sangnto hernwhile she died
dssds
he will risk his life to save hers. And that he will protect her in anyway he can.
Katniss and Peeta believe that both of them can win The Hunger Games. However, when just the two of them are left, The Gamemakers annouce that only one person can live. Katniss pulls out 'nightlock,' which are berries that will kill you before they reach your stomach. The capitol thinks she is defying them and this is an act of rebellion, but The Gamemakers let both Peeta and Katniss live. Peeta and Katniss win The Hunger Games as a team. Katniss then finds out that Peeta really does love her, but she tells him that she was only pretending to be in love with him in order to save them.
Because Peeta loves Katniss
Katniss is determined because she thinks in the end she can save Prim (her little sister.)
Katniss is not really a people person.
When her sister Primrose got chosen during the reaping, Katniss volunteered to be a tribute. To save Prim's life.
Yes
Prim is the only person that Katniss knows she loves. She tries to protect Prim in every way she can.
Katniss everdeen
She doesn't like it but she goes to save Peeta's life
Thresh. He spared Katniss's life because she partnered with Rue and tried to save her when she died.
Katniss and Peeta believe that both of them can win The Hunger Games. However, when just the two of them are left, The Gamemakers annouce that only one person can live. Katniss pulls out 'nightlock,' which are berries that will kill you before they reach your stomach. The capitol thinks she is defying them and this is an act of rebellion, but The Gamemakers let both Peeta and Katniss live. Peeta and Katniss win The Hunger Games as a team. Katniss then finds out that Peeta really does love her, but she tells him that she was only pretending to be in love with him in order to save them.
At the end of Mockingjay, Katniss chooses Peeta.
She promised to save Peeta and let him win the quarter quell.