REST service in regional language using utf8

When we want to display regional language from the database , we have to use utf8 formate

so 

mysqli_set_charset($conn,"utf8");

this line of the code must be added after the connection before the SQL


<?php

  ini_set('display_errors', 1);  
 ini_set('display_startup_errors', 1);
 error_reporting(E_ALL);
 //header("Content-Type: text/html;charset=UTF-8");
 $mysql_hostname = '*************';
 $mysql_user = '******';
 $mysql_password = '*********';
 $mysql_database = '**********';
 //echo "*************************************";
 //var_dump(function_exists('mysqli_connect'));
 $conn = new mysqli($mysql_hostname, $mysql_user, $mysql_password, $mysql_database);
 if (!$conn){    
 die("Connection error: " . mysqli_connect_error());  
 }
 // Change character set to utf8
mysqli_set_charset($conn,"utf8");
 $sql = "SELECT * FROM  wp_bestcinemaposts ";
 $rows = array();
 $result = mysqli_query($conn, $sql) or die(mysqli_error($conn));
 while ($row = mysqli_fetch_assoc($result)) {  
$res=array();  
$rows[] = $row;
 $post_parent=$row['ID'];  
 //echo '***************',$row['post_content'];
 }
 print json_encode($rows);
/
 ?>