You can find the hints and solution below.
For just the solution, scroll all the way to the bottom of the page.
Can you match the patterns on the hearts on front of the card to the patterns on the letters on the back?
Do you remember what the Koala's message is?
"You make my heart grow"
Perhaps that is a hint.
Have you tried arranging the hearts in smallest to largest order?
If you replace the hearts with the letters that match the corresponding pattern, while the order of the hearts is sorted like in Hint 8, you should see a secret message.
The front of the card has a message that says, “You make my heart grow”. There are also several hearts with different patterns on them. The back of the card has letters with the same pattern as the front.
These can be associated as such:
Following the Koala’s message, you should be able to sort the hearts like this:
Now substitute the hearts for their corresponding letters. This should reveal a secret message.
The solution is: LOVE AND HUGS.