use HTML::Entities;
use strict;

my $input = 'Не просто';
$input = decode_entities($input);

# Sendmail stuff
my %mail;
$mail{'Content-type'} = 'text/plain; charset="utf-8"';
$mail{smtp} = 'smtp.mycompany.com';
$mail{From} = 'server@mycompany.com';
$mail{To} = 'me@mycompany.com';
$mail{Subject} = 'Sendmail Test';
$mail{Message} = $input;

use Mail::Sendmail;
Mail::Sendmail::sendmail(%mail) || print STDERR $Mail::Sendmail::error;