I’m not quite sure about your code,
here is an example with a long tool-tip value:
Element:
<a href="#" rel="tooltip" title="Lorem ipsum dolor sit amet, consectetur adipiscing elit. Maecenas bibendum ac felis id commodo. Etiam mauris purus, fringilla id tempus in, mollis vel orci. Duis ultricies at erat eget iaculis.">Hover here please</a>
Js:
$(document).ready(function () {
$("a").tooltip({
'selector': '',
'placement': 'top',
'container':'body'
});
});
Css:
/*Change the size here*/
div.tooltip-inner {
max-width: 350px;
}
Demo: on JsBin.com
Apprently you can only change the .tooltip-inner in Bootstrap 4, thanks @Felix Dombek
.tooltip-inner { max-width: ... }