text: The most important sign to a trustworthy merchant is a secure website.  Many merchants look for a website that is secured with an SSL certificate.  The design of the website can impact whether someone will make a purchase or not.  A reputable site will look reputable.  You will sell more if you make it easy for people to purchase from your site.  If you are in the United States, you could also register with the BBB to display an icon on your website.  Most people recognize and trust the BBB logo.