Wireless sensor networks are easily compromised by an adversary, such as fabricated with false votesattacks and false votes on real reports attacks. These attacks generate false data to drain the energyresource of sensors and interrupt the inflow of a real report. PVFS was proposed to detect them byverifying votes in the real report. When a real event occurs, a cluster head collects all of the votes from itsneighboring nodes and selects the votes up to a defined number of votes. In this paper, our proposedmethod decides the number of votes based on a fuzzy rule-based system to improve energy savings ascompared to PVFS. We evaluated the effectiveness of the proposal as two attacks occur simultaneously inthe sensor network. The experimental results show that our method saves energy resources and maintainsthe security level against these multiple attacks.