Final answer:
The 20-year-old woman who was recently raped is likely to face the most difficulty in being assertive due to the potential impacts of trauma on her psychological state and self-esteem.
Step-by-step explanation:
In assessing which of the clients is most likely to experience difficulty in being assertive, it is important to consider the individual's current psychological state and environmental factors. Among the listed clients, a 20-year-old woman who was recently raped may face significant challenges in assertiveness due to potential post-traumatic stress and the impact that such an experience could have on her self-esteem and sense of control. The traumatic nature of the event could lead to a difficulty in being assertive as the individual may struggle with feeling vulnerable or powerless.