Multi-language character support in Thymeleaf

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8"/>
</head>

<!--<body style="width: 900px; margin: 0 auto; color: #111; font-family: Arial Unicode MS; font-size: 12px;-->
<!--    line-height: normal; box-sizing: border-box;">-->
<body style="font-family: Barlow">

<div>
    Sample test text
    tiếng Việt
</div>

</body>
</html>

templateEngine.process("template.html", context);

I am using this template.html file with Vietnamese text in it
and trying to generate pdf from it by using Thymeleaf.TemplateEngine
but,
text is comming like this in pdf