It's when you love someone more than they love you even though they used 'mostest'.
In most cases, 'mostest' can't be beaten, but there are always special exceptions, such as 'I love you more than mostest'
Person 2. : *oh damn what do I say I can't accept this because it isn't true!!!* I love you more than mostest.
Person 1 : Shucks, you got me there. I'll have to accept your love then
The way I feel about you Melissa. You've made me happier than I ever thought possible. I never want to be without you again and I want to spend the rest of our lives together. That would make me the happiest person alive.