How to search using ajax for exact phrase or words in an input field?

This is more of an hack but i couldn’t find any other way around, tried exact= "true" and sentence="true" as parameters in the query but still, i had all results not only the exact matching one. Therefore since I was having the results as a list, i am doing a check in the DOM and removing anything which doesn’t exactly match the .val()

function searchAjax(){
  jQuery.ajax({
    url: '<?php echo admin_url('admin-ajax.php'); ?>',
    type: 'post',
    data: { action: 'data_fetch', exactwords:  jQuery('#usp-title').val() },
    success: function(data) {
      var text2;
      var text2B;
      text2 = jQuery('#usp-title').val();
      text2B = text2.toLowerCase();
      jQuery("#datafetch").html(data).promise().done(function(){
        jQuery("#datafetch ul li h2 a").each(function() {
          var $this = jQuery(this);
          if ($this.text().toLowerCase() !== text2B) {
            $this.parent().parent().remove();
            jQuery(".jumbotron").remove();
            jQuery("#componi").removeAttr("disabled", "disabled").show();
          } else if ($this.text().toLowerCase() == text2B) {
            jQuery("#componi").attr("disabled", "disabled").hide();
          }
        });
      });
    }
  });
}