Hi everyone!

Often I come across the words "I'll tell you that much" in writings and have no idea what they mean.

What is the meaning of those words and in what kind of situation are thy used?

A writing I came across is the one below.

So, if anybody know the meaning and would tell me, I would appreciate it.

Thanks a lot in advance!


[An example]

"It’s just a nasty, disease-carrying little pest! This disgusting little creature won’t bother anyone again, I’ll tell you that much!"
I'll tell you that much = I am confident/sure of that fact.
I definitely can tell you that ...