Which aspect of self relates to the belief in one's own effectiveness and control over life outcomes?

Self-efficacy

Self-efficacy is another important aspect of our self. People differ in the extent to which they believe they themselves control their life outcomes or the outcomes are controlled by luck or fate or other situational factors, e.g. passing an examination. A person who believes that s/he has the ability or behaviours required by a particular situation demonstrates high self-efficacy.