Answer:
The change in Manuel's heart is brought about by the suspicious behavior of Tomiko in frequently disappearing into the night and the presence of the same red fox he had fed in the desert before.
Explanation:
The story of "Manuel and the Magic Fox" by Ekaterina Sedia revolves around the protagonist Manuela and the red fox that he'd helped in the earlier part of the story. He had fed the fox and the fox had come back as a young Japanese girl named Tomiko to help Manuel and his sick mother.
At first, when Tomiko came to help out, Manuel felt <em>"renewed and confident"</em> in managing their daily life. He now has a partner to help out in the work. But then, he began to experience anxiety and resented Tomiko. This was brought about by the appearance of the same red fox one night. Even though he didn't think much about it, the fox's appearance in their garden led him to be anxious about something. And he did not think much about the occurrence, and even with the frequent disappearance of Tomiko at times, almost every night. But as it would have been, he started to be suspicious of her actions. He also <em>"grew resentful that she asked for his trust, while she did not offer hers"</em>. This mainly caused the change of heart in Manuel, for he felt that Tomiko also have the right to offer her trust and not expect only from him.