The discussion on whether hedges can contribute to the construction of reliability and maintenance of interpersonal trust has been a hot issue in recent linguistic research. In order to map out the relation between hedges and reliability construction, this paper aims to conduct a quantitative-and-qualitative research of hedges by a self-built corpus of the U.S. presidential candidates debates. This paper explores the types and functions of hedges by using the corpus. Based on the analysis, this paper investigates the trust value of different hedges through a survey of 65 native English speakers from the U.S. It is found that hedges used by the candidates could be classified into quantity hedges and topic hedges. The main function of quantity hedges is to avoid responsibility, while the main function of topic hedges is to highlight the speaker’ s sincerity and maintain a harmonious relationship. Both of the hedges are conducive to reliability construction and maintenance of interpersonal trust. It is hoped that this paper would contribute to both the theoretical study of hedges and the practice of interpersonal trust management.