How to bless your girlfriend's mother on Mother's Day?

I think your girlfriend's mother should already know about you in this case, right? In view of this situation, you can send short messages like this (personally, short messages, as a kind of text, are more suitable for expressing feelings)

Happy Mother's Day!

I am xxx's boyfriend, and I love/like her very much. Her temperament and conduct attract me all the time. All this is brought to her by your mother. She is as great as other mothers in the world. Here, I would like to extend my deep respect and sincere greetings to you and wish you a happy holiday again.

Sincerity from xxx

This should be about the same, just right.