Hi Ron, the headings underline is part of the design of the Trusted theme and it takes the color of the Primary Color setting. See the attached image below.
The next update of the theme will have an option to remove this styling, but if you need to remove it now, add this in Customize > Additional CSS:
.entry-content h1:before, .entry-content h2:before, .entry-content h3:before, .entry-content h4:before, .entry-content h5:before, .entry-content h6:before,
.entry-content h1:after, .entry-content h2:after, .entry-content h3:after, .entry-content h4:after, .entry-content h5:after, .entry-content h6:after {
display: none;
}