The first solution that occurred to me is shown in the following code. Note that I considered splitting the input text on spaces, and that may not be a solution for you depending on your actual input and the patterns you are looking for.

use strict;
use warnings;
use Data::Dumper;

my $text = "match other match not useful match sample word";
my $string1 = "match";
my $string2 = "not";
my %repetitions;
map {$repetitions{$_}++;} grep /$string1|$string2/, split / /, $text;
print Dumper(\%repetitions);

### Outputs:
$VAR1 = {
          'match' => 3,
          'not' => 1
        };
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