JSFiddle - React, Tailwind, and code Playground

HTML

<p id="js-show-more-toggle" class="neutral fssm">
        This long, lean, seductive case is packed with TWELVE gorgeous neutrals. Shades range from delicate champagnes to dark, gritty gunmetal, and feature FIVE NEW shades with names like Darkhorse, Virgin and Buck. <br />
        <br />
We've also included a range of textures: everything from glitter to shimmer to matte. The chocolaty velvet case is emblazoned with the word "NAKED" in gold foil lettering. (Just wait 'til your friends see you pull this sexy thing out of your bag. Jealous!) <br />
        <br />
The mirrored case also includes a professional quality, cruelty-free Good Karma Eyeshadow Brush, AND a travel-size Eyeshadow Primer Potion in original formula. <br />
<br />
This is a shadow palette EVERYONE can use, and a truly spectacular gift. Experiment with office-appropriate neutrals, summertime bronzy looks, or sultry smokiness. With such a diversity of neutral shades at your fingertips, there's more to neutral than meets the eye!
    </p>

CSS

.faded {
    display: none;
}

JavaScript

jquery(function() {
    // Target everything after the 2nd <br>
    var $marker = $("#js-show-more-toggle br:eq(0)");
    // Our wrapper for the content in the show more
    var $wrapper = $("<div>", {
        class: "faded"
    });
    var $more = $('<a>', {
        href: '#',
        id: 'js-show-more'
    }).text('Show More');

    var seen = false;

    // Look through all text
    $("#js-show-more-toggle").contents().each(function() {
        if (seen) {
            $wrapper.append(this);
        } else if ($(this).is($marker)) {
            // This is what we want to show
            seen = true;
        }
    }).end().append($wrapper).append($more);

    $more.delegate(this, 'click', function(e) {
        e.preventDefault();
        $(this).prev($wrapper).slideToggle('slow').toggleClass('js-show-more js-show-less');
        if ($(this).text() == 'Show More') {
            $(this).text('Show Less');
        } else {
            $(this).text('Show More');
        }
    });

});