We present a trust-enabling intermediation system architecture for intelligent decision support in e-tourism applications, namely the Trust Intermediary Service Provider (TISP) system. The purpose of the present work is twofold: to propose a trust-building conceptual framework to account for customer trust in e-commerce applications; and to present a system architecture for knowledge-based decision-making support in the e-tourism context, as a technological demonstration fitting most of the trust-enabling mechanisms in the conceptual framework. The presented system aims to demonstrate the technological feasibility of a semantic-web-based architecture capable of meeting personalised needs and interests in interacting with an e-tourism intermediary, while allowing mechanisms to support trust building and maintenance. The core TISP components are designed for high reusability and are based on advanced knowledge-management-enabling technologies as well as design patterns derived from the Semantic Web (SW) and artificial intelligence fields of study.