_____ describes the likelihood that if a person tries to perform better, that will really be the result.

The concept you are referring to is known as self-efficacy. Self-efficacy is a psychological construct that reflects an individual's belief in their ability to succeed in specific situations or accomplish a task. It plays a critical role in determining how people approach challenges and goals. High self-efficacy can lead individuals to take on difficult tasks and persist in the face of adversity, while low self-efficacy might make individuals avoid challenging tasks, as they may doubt their abilities. This concept was introduced by psychologist Albert Bandura and is fundamental to understanding motivation, behavior change, and performance outcomes. In essence, self-efficacy influences the likelihood of success based on individuals' beliefs in their capabilities.