The appropriate nursing diagnosis for a client needing help with assertiveness is Impaired verbal communication. This diagnosis addresses the person's ability to express themselves verbally, which is a key component of assertiveness.
A nurse should assign the nursing diagnosis of Impaired verbal communication to a client needing assistance with assertiveness. This diagnosis is suitable because assertiveness relates to the ability to express one's feelings, needs, and thoughts in a direct, honest, and appropriate way. When a person struggles with assertiveness, they often have difficulties in effectively expressing themselves verbally, which can impact their relationships and interactions with others.
In contrast, the other options, such as Disturbed personal identity, Disturbed thought processes, and Defensive coping, do not directly address the skills and capabilities associated with verbal communication and assertiveness. Therefore, Impaired verbal communication is the most accurate nursing diagnosis for someone who requires help developing assertiveness skills.
Final answer in two lines: The correct nursing diagnosis for a client in need of assertiveness assistance is Impaired verbal communication.