The need for adaptive systems is growing with the increasing number of autonomous entities such as software systems and robots. A key characteristic of adaptive systems is that their environment changes, possibly in ways that were not envisaged at design-time. These changes in requirements, model and context mean the functional behaviour of a system cannot be fully defined in many cases, and consequently formal verification of the system is not possible. In this research, we propose a fuzzy representation to describe the result of requirement verification. We use an adaptive assisted living system as the case study. The RELAX language is used to create a flexible system specification. We model and simulate the system using UPPAAL 4 and use a fuzzy approach to translate the simulation result into fuzzy requirement satisfaction. The result shows the benefit of a more flexible representation by describing the degree of requirement satisfaction rather than a strict yes/no Boolean judgment.