Uncertainty and instability are two main things what we face every day in our new reality. Life-sustaining beliefs certainly influence the assessment of the situation because it is perceived as less traumatic due to its willingness to act actively and confidence in the ability to influence the situation. Theoretical substantiation and empirical research of the features of personality sustainability in critical living conditions became the purpose of this study. The significance of the hardiness of the person in today’s changing conditions (the creation of the basis of internal harmony, complete mental health and high capacity for life) has been established. The essence of hardiness as a resource for the adaptation of the individual in society has been revealed. As a result of the conducted research, it has been established that the general level of hardiness affects self-development, passion, optimism, and adaptability. It has been determined that the indicators of adaptation have positive significant relationships with all components of hardiness and its general indicator. It has been confirmed that “involvement” as a component of hardiness has significant relationships with emotional comfort and close to significant relationships with self-acceptance and internal control. It has been established that indicators of “risk acceptance” are inversely proportional to the indicator of maladaptation. Statistical analysis has proved that the indicator “control” is significantly positively correlated with the indicators: “conditions of self-development” and “optimism”. The higher the indicator of person’s hardiness, the more clearly expressed the indicators of self-acceptance and emotional comfort. It has been found that a medium level of hardiness contributes to the optimal experience of uncertain situations and includes the individual’s choice of coping strategies that allow him to face new challenges in his professional and personal life. Respondents with high indicators of hardiness have a high level of adaptation efficiency.