h1 { color: #666;display:inline-block; margin:0;text-transform:uppercase; }
h1:after {
display:block;
content: '';
border-bottom: solid 3px #019fb6;
transform: scaleX(0);
transition: transform 250ms ease-in-out;
}
h1:hover:after { transform: scaleX(1); }
h1.fromRight:after{ transform-origin:100% 50%; }
h1.fromLeft:after{ transform-origin: 0% 50%; }
<h1 class="fromCenter">Expand from center</h1><br/>
<h1 class="fromRight">Expand from right</h1><br/>
<h1 class="fromLeft">Expand from left</h1>