What is Trust Flow?
According to Majestic SEO, Citation Flow is a number of predicting how influential an URL may be based on how the number of websites that link to it. Trust Flow is a number predicting how trustworthy a page is based on how trustworthy sites tend to link to trustworthy neighbours. You can learn more about trust flow here.
Sites closely linked to a trusted seed site can see higher scores, whereas sites that may have some questionable links would see a much lower score.
Trust flow is based on the QUALITY of backlinks pointing back to your website.
Increasing trust flow should be the main goal of your SEO and this can be done by getting high-quality backlinks back to your website.