Well, I know I'm a million times as humble as thou art"
"in fact, I'm much more humble than you could understand"
"In fact, I am the least bragging person in the world. No one brags less than me."
I considered downvoting you for needless bragging, but I did not - I think I am a better person that way.
> I am proud to say I have never bragged in my life.
How is that figure of speech called in English?
You might call it "tongue in cheek" in the UK, a statement made with no pretense that it's true, with a gently humorous intent.
If anyone is wondering, "tongue-in-cheek" is also a term used in the US.
I would call it sarcasm, except it's too funny for me to simply label it sarcasm.... Not that sarcasm can't be funny, it just sometimes has such bad connotations.