This study aims to develop a scale to measure tourists' trust in Gilan province as one of the most attractive tourist destinations in the country using a mixed approach. Qualitative data were collected using semistructured interviews with twelve academic experts, policymakers and tourism planners. Data analysis using grounded theory, in two stages of basic and theoretical coding, lead to the extraction of 48 concepts, 19 sub-categories and finally 6 main categories of trust in tourism destination management, travel agencies, tourism service providers, tourist destination residents, other Tourists and cyberspace content,it became a dimension of trust in the tourism industry. In a quantitative stage, a questionnaire was prepared based on the extracted components and provided to 389 tourists visiting different cities of Gilan province. The validity of the model was reaffirmed using exploratory and confirmatory factor analysis. Introduction The tourism industry has significantly strengthened local economies in the last two decades. Considering the importance of tourism and its competitive market in the world, tourism destinations to attract tourists are in close competition with each other, and each tries to increase its share of the industry's revenues. However, with the recent events, such as unfair or fraudulent behavior and failure to provide services as promised, the crisis of trust in tourism has increased and become an important issue. Trust is a prerequisite for improving many marketing variables, including loyalty, travel intent, destination attachment, and repeat visits. To date, a comprehensive scale for constructing tourist trust in a tourist destination has not been provided. Most researchers in tourism studies have borrowed trust measurement tools from other sectors such as social sciences, branding, and ecommerce. Some have developed this scale in a specific area of tourism, for example, medical tourism and shopping, and some have made the scale acceptable using a qualitative approach without credibility. Therefore, to fill the gap in the tourism literature, develop a more comprehensive and multidimensional scale for tourist trust that considers different stakeholders. A systematic review of the research literature showed that a comprehensive scale for constructing tourist trust in a tourist destination had not been provided. Therefore, to fill the gap in the tourism literature, it is essential to develop a more comprehensive scale for tourist trust. Materials and Methods The present research has been conducted with a hybrid approach (qualitative-quantitative). Data analysis and design of the trust measurement scale were based on the grounded theory. The statistical population in the qualitative section includes academic experts, policymakers, and planners in the field of tourism in Gilan and tourists. Samples were selected using the purposive sampling method (12 people). In this study, a combination of validity, transferability, reliability, and verification criteria was used to assess the reliability of the interview interpretation. Quantitatively, the statistical population includes tourists visiting different cities in Gilan province. The non probability sampling method is available. The statistical population includes 389 tourists visiting different cities in Gilan province were analyzed. Exploratory and confirmatory factor analysis was used to ensure the validity of the structures and identify the main dimensions and factors that build the trust of tourists extracted from the interviews. Discussion and Results In the quality section, in the combination of selected codes, trust in tourism destination management, trust in travel service agencies, trust in the staff of tourism service providers, trust in residents of tourist destinations, trust in other tourists, and trust in cyberspace content,forms the dimension of trust in the tourism industry. In the quantitative part of the research, 389 incoming tourists to Gilan province were analyzed. The results of exploratory and confirmatory factor analysis that were used to ensure the validity of the structures and identify the dimensions and underlying factors of the six main variables of tourist trust showed that the six research structures have the necessary accuracy in measuring their structures. Conclusion The comparison of previous studies with the research results reveals its differences with the existing literature and the innovation of the research. The proposed research scale for measuring tourist trust is relatively comprehensive. It covers the different perspectives of destination stakeholders (management, travel agencies, staff, residents, other tourists, and cyberspace content) at both institutional and interpersonal levels. On the other hand, tourism research relies solely on trust by focusing on one or more groups of organizational stakeholders, such as the government, studied by tourism institutions and travel agencies or among tourists, residents, and travel guides. Measurement indices for each dimension also cover more components than similar previous studies. In addition, the proposed scale is presented with an overview. Unlike some previous studies, it has not been done with an emphasis on a specific type of tourism such as etourism, medical tourism, or shopping tourism. Thus, it is a more reliable scale for measuring various dimensions of trust.