Displaying long text in Bootstrap tooltip

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: ... }