and random guesses hasn't worked either

You obviously don't have enough monkeys.

But seriously, here what the documentation says about capitalisation.

d:\>perldoc -q capitalize
Found in D:\Perl\lib\pod\perlfaq4.pod
  How do I capitalize all the words on one line?
    To make the first letter of each word upper case:

            $line =~ s/\b(\w)/\U$1/g;
[download]

There's also good information at perldoc -f boundary, which might help clarify your thinking about what constitutes a word boundary.