wow,thank you for your answer!☺

It is the result of using a secret code where each letter actually represents a different letter. This is not something you would see in everyday language, but this code means, "I love you." Here is a link to a page with a good explanation of how the code applies. https://itspctrick.blogspot.com/2015/07/how-is-i-love-you-encrypted-to-p-zqae.html