PHP Mysql Json encode and Arabic language

Question

I used

header('Content-type: text/plain; charset=utf-8');

and

1. MySQL charset: UTF-8 Unicode (utf8)
2. MySQL connection collation: utf8_general_ci
3. your database and table collations are set to: utf8_general_ci or utf8_unicode_ci

and every time I try to output the json by using echo json_encode($return_arr); I get like this

[{"item_id":"497c5fe455811cb88d66d98da7e11abd","title":""\u0627\u0644\u064a\u0648\u0645 \u0627\u0644\u0633\u0627\u0628\u0639": \u0645\u0641\u0627\u062c\u0623\u0629.. \u0642\u0627\u0646\u0648\u0646 \u0627\u0644\u0625\u0631\u0647\u0627\u0628 \u0645\u0647\u062f\u062f \u0628\u0639\u062f\u0645 \u0627\u0644\u062f\u0633\u062a\u0648\u0631\u0