How did Katniss react when she learned that Peeta wanted to train alone?

Katniss did not show any reaction when she learned that Peeta wanted to train alone but felt betrayed inside.

Explanation:

Haymitch asked Katniss and Peeta if they wanted to train together or separately. The tributes from the same district had the choice of training separately if they did not want the other one to know their strengths and weaknesses. In the beginning, Peeta and Katniss agreed to train together.

After they received their scores from the Gamemakers, Peeta told Haymitch that he wanted to train separately from Katniss. When Katniss learned about it, she did not show any reaction but on the inside, she felt betrayed by him since they were from the same district. While there was the feeling of betrayal, there was also a feeling of relief as she realized they could stop pretending to be good friends with each other in front of people.