Based on the provided story, here is the JSON output evaluating its Tragedy Degree and Comedy Degree:

{
  "TragedyDegree": 4,
  "ComedyDegree": 3
}

Explanation:
- **Tragedy Degree of 4**: The story includes tragic elements such as the desperate situation of Thomas trying to save his gravely ill sister, and the emotional conflict faced by Sir Tristan in deciding whether to adhere strictly to his duty or to act with compassion. However, it does not reach a level of profound tragedy with strong emotional impact.
- **Comedy Degree of 3**: The story is relatively serious, with almost no comedic elements. It has a somewhat positive resolution with Sir Tristan's compassionate decision, but it doesn't contain significant light-hearted or humorous moments, nor does it end in an extremely happy or emotionally delightful manner.
