Apart from the info provided above, I like to think CF as the number of links from article type of pages that are pointing to your site. The more article links you build, the higher the CF would go.
Pumping links from article sites do not increase TF. Trust as the name implies, is how trust worthy your site is, in which they would spend a considerably more time on your site, and there will be engagements on the site as well, such as browsing pages, and visiting the links that are on the web page itself, which contributes to TF. TF is difficult to fake, and spam links do not increase TF at all.