Undoubtedly, it is in which you were doubting
This is what you used to doubt.
This is that which you doubted.
Surely this is what you doubted
That truly that (is) what you were with it doubting/arguing
This is what you were mocking at.”
“Indeed this is what you used to doubt about.”
`This, indeed, is what you doubted.
Certainly, this is the very Hell you used to doubt.
`This of course is (the very punishment) about which you used to wrangle.
"Verily! This is that whereof you used to doubt!"