从XML获取值时Wordpress remove_accents（）无法正常工作

I have special problem. I'm using WP All Import Pro plugin to import XML to Wordpress posts.

I need use WordPress function remove_accents() for strip Czech accents (ěščřžýáíé) for post slug.

If I set variable manually (ignore $mytitle), all works fine.

function seofriendly_slug($mytitle) {
    $finalslug = remove_accents("Test string ěščřžýáíé");
    return $finalslug;
}

OUTPUT: Test string escrzyaie

But if I use variable $mytitle that coming from XML (utf8):

[seofriendly_slug({PRACOVISTE[1]/@nazev})]

Variable is set propertly but remove_accents does not work:

function seofriendly_slug($mytitle) {
    $finalslug = remove_accents($mytitle);
    return $finalslug;
}

OUTPUT: Test string ěščřžýáíé

Last info: When I use mb_detect_encoding($mytitle), output is "ASCII" but in XML header is UTF-8.

I get solution from WorkScout theme creator - PureThemes.

html_entity_decode($prepareslug, ENT_QUOTES, 'UTF-8');

Final code:

function seofriendly_slug($nazev,$doplnek,$obec) {
    if ($doplnek ==NULL) { $titulek = $nazev; } 
        else { $titulek = $doplnek; }
    $prepareslug = $titulek."-".$obec;
    $prepareslug = html_entity_decode($prepareslug, ENT_QUOTES, 'UTF-8');
    $finalslug = sanitize_title($prepareslug);
    return $finalslug;
}