Effective nursing notations and the nurse/patient relationship are essential for mental health nursing. Therefore, both elements should be included in mental health education and nursing training. Understanding the dynamics involved, however, can be challenging for undergraduate nursing students. Commonly, students from the University of Talca would omit crucial details that were necessary to properly analyze a patient's state of mental health. Some students did not know how to go about establishing professional relationships with the patients. For this reason, a patient assessment guide is highly recommended. This allows for the students to improve their assessment skills. The main objectives that motivated the design of this tool were to support the nursing student’s learning process, promote a systematic record of the main phases of the therapeutic relationship, and apply specific verbal and non-verbal techniques to communicate well with patients. This evaluation form was designed according to Peplau’s middle-range theory of interpersonal relations. The form includes the three phases of the interpersonal relationship: orientation, working, and termination, where the students are required to describe them according to the patient’s characteristics and needs. This cost-effective tool has significantly facilitated the student’s learning and training in mental health nursing, specifically the importance of the therapeutic relationship. During the two years when this tool was in practice, students improved their understanding of the main factors involved in the nurse/patient relationship. This nursing form also helps nursing students identify the main aspects involved in mental health assessment. Using this tool has facilitated mental health training for undergraduate nursing students while improving the quality of nursing assessment, ultimately providing high-quality nursing care in mental health.