$Label.Site

A global merge field type used to reference a standard Sites label in a Visualforce page. As with all standard labels, the label’s message displays according to the user’s language and locale. You can’t modify the message of a standard Sites label. To use a custom message, create a custom label, and then reference the label with the $Label global variable.

1<apex:page>
2    <apex:pageMessage severity="info" 
3        strength="1" 
4        summary="{!$Label.Site.temp_password_sent}" 
5    />
6</apex:page>