I think to write a letter of guarantee, first make the question clear, and then write it according to the following steps:

1. Title: "Guarantee".

2. Text: Acknowledge the existing problems and put forward specific improvement measures and plans. Describe the problem objectively and truly, express reflection and understanding; Improvement measures should be concrete, feasible, quantifiable and evaluable.

3. Conclusion and signature: emphasize determination and commitment, express expectations and confidence in the future, and thank teachers and parents. Signature and date.

Think carefully and revise it repeatedly when writing to ensure that the content is true, concrete and feasible.