html实体解码不会删除像<b>这样的html元素

I have this string that contains html, p ,div, b

$string = "this is a <b> test </b>";

echo html_entity_decode($string, ENT_QUOTES, 'UTF-8');

When I echo it on my page it is shown like this:

this is a <b> test </b>

What should I do to make it work properly?

Desired result :

this is a test

Use htmlspecialchars_decode.

echo htmlspecialchars_decode($string);