According to Majestic SEO, Trust Flow is a number predicting how trustworthy a webpage, such as a location or a geo page, is based on how trustworthy sites tend to link. There is a difference between citation flow and trust flow, but the two ranking factors work together.
All links are not all created with equal weight. Because a strong link will have a relatively stronger influence on URLs, Citation Flow is based on an iterative mathematical logic to evaluate ranking probability based on links.