What does compelling mean? Her sadness was compelling.?
evoking interest, attention, or admiration in a powerfully irresistible way.
Compelling is the action word for Compel or Compelled. In this case, 'Her sadness was compelling'. it is talking about the subject- sadness that is compelling. This statement basically means the reader or watcher will feel sadness and emotion due to the sadness portrayed by the character, in this case 'her'.