Trust is important for every social network and for most of the mobile applications. However, it is not considered well in many projects and would need more attention. In this thesis I explore how trust can be generated in community-based mobile applications. In social networks trust plays an important role. Especially in social networks like the Open- Share-It project, which is described in this thesis, trust can be essential for the success of the application. The users do not only have to trust in the social networks and their users, but also in the meetings in real life and the food they share. An important question in this context is how the user-s trust in the application can be strengthened. Another important question is how trust between the users can be supported by the application. I did literature research, carried out interviews and made a survey to explore the creation of trust in such networks. Furthermore, the Open-Share-It project, which has been developed at the Vienna University of Technology, is presented, and its relevance for this thesis is described in more detail. The experiences of this project influence the end results. The results are synthesized in guidelines and compared with the Open-Share-It project. With the guidelines I intend to offer advice about how trust between users can be enhanced by the application and about how the user-s trust in the mobile application can be increased.