problem with accentuation in autocomplete jquery [duplicate]

I have a UTF-8 problem in my code. I have a input text with autocomplete (jquery function) that works ok with results coming from MySQL, but when a word is accented with the accented letter appears a question mark (?). Here is my code:

  

return_process_process.php

<?php require_once("conexao/conexao.php"); ?>
<?php
$term = trim(strip_tags($_GET['term']));//retrieve the search term that autocomplete sends

$qstring = "SELECT clienteNome as value,clienteId as id FROM cliente WHERE clienteNome LIKE '%".$term."%' LIMIT 10";

 $consulta_tr = mysqli_query($conecta, $qstring);
    if(!$consulta_tr) {
        die("erro no banco1");
    }

while ($row = mysqli_fetch_array($consulta_tr,MYSQL_ASSOC))//loop through the retrieved values
{
        $row['value']=htmlentities(stripslashes(utf8_decode($row['value'])));
        $row['id']=(int)$row['id'];
        $row_set[] = $row;//build an array
}
echo json_encode($row_set);//format the array into json data
?>

  

js function

$(document).ready(function() {

        $('#clientes').autocomplete({
        source: 'php/retornar_cliente_processo.php',
        minLength: 1,   

          select: function(event, ui) {

            $('#clienteId').val(ui.item.id);
            $('.form-control').removeAttr("disabled");  
            $('#clientes').attr("disabled", "disabled");
            $('#alteraNome').removeAttr("disabled");        
                 },
            }); }

  

html

 <form class="form-horizontal" id="formCad">

      <input type="hidden" name="clienteId" id="clienteId" placeholder="ID">   

          <div class="form-group">
              <div class="col-md-12">
                  <label for="clienteNome" class="control-label">Nome do cliente</label>

                  <div class="input-group">
                      <input type="text" autocomplete="off" name="clienteNome" id="clientes"  class="form-control" placeholder="Nome do cliente" required>

                  </div>

            </div>
          </div>