JSFiddle - React, Tailwind, and code Playground

HTML

<div id="plav-text">
тут текст, который медлеонно# появляется.
</div>

CSS

#plav-text{display:none;}
            #plav-text .new{opacity: 0;}
            #plav-text .div_opacity{
            -webkit-transition: opacity .1s ease-in-out;
            -moz-transition: opacity .1s ease-in-out;
            -ms-transition: opacity .1s ease-in-out;
            -o-transition: opacity .1s ease-in-out;
            transition: opacity .1s ease-in-out;
            opacity: 1;}

JavaScript

$.fn.animate_Text = function() {
    var string = this.text();
    $(this).html('');
    return this.each(function(){
        var $this = $(this);
        string.split('').forEach(s =>  s == "#" ? $this.append('<br>') :$this.append('<span class="new">'+s+'</span>'))
        //$this.html(string.replace(/./g, '<span class="new">$&</span>'));
        $this.find('span.new').each(function(i, el){
            setTimeout(function(){ $(el).addClass('div_opacity'); }, 59 * i);
        });
    });
};
$('#plav-text').show();
$('#plav-text').animate_Text();