What word describes a situation that causes great sadness or pessimism?

The word that best describes a situation causing great sadness or pessimism is "dismal." This term conveys a sense of gloom or despair and is often used to describe circumstances that are bleak or dreary. In this context, a dismal situation evokes feelings of disappointment and hopelessness, perfectly encapsulating the essence of sadness and pessimism.

The other words do not align with the specific meaning required by the question. "Confounded" typically refers to being confused or perplexed, rather than sad. "Affluent" indicates wealth and prosperity, which does not relate to feelings of sadness or pessimism at all. "Reticent" refers to a reluctance to speak or disclose one's thoughts, which again does not convey a sense of gloomy or pessimistic circumstances. Therefore, "dismal" is the most fitting choice for describing a situation that evokes great sadness or pessimism.