JSFiddle - React, Tailwind, and code Playground

HTML

<div class="activator">
  навёл
  <div class="content-l1">
    появилось
  </div>
</div>

CSS

.content-l1 {
  transition: 0s;
  opacity: 0;
}

.activator:hover>.content-l1 {
  opacity: 1;
  transition-delay: 0.5s;
}