I'm confused. There are 40 characters in that string!

Note too that the characters you have posted render as utf-8 characters (at least for me).

The following may help however:

use strict;
use warnings;
use Encode;

my $str = "הההההההההההההההההההההההההההההההההההההההה";

print 'Raw: ' . length $str;
print "\nDecoded: " . length decode ('utf8', $str);
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Prints:

Raw: 80
Decoded: 40
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If the encoding you are using really is latin1 then using decode ('iso-8859-1', $str) may turn the trick for you.