This was Shindong's thanks to in the 4th album:
The code can be understood with this
A is the 1st row (Q,W,E.R....)
B is the 2nd row (A,S,D,F...)
C is the 3rd row (Z,X,C.V...)
the number next to the letter is the key in that row (from the left to right)
and you end up with something in Korean:
Which is translated to:
let's get married,
this is a proposal,
i'll love you,
Credits to Korean ELF for solving the code.
Sophia for the translation
Again, we do not know what this can mean, if it's a real proposal or a joke.
Please wait for any kind of confirmation from Shindong himself.