Don’t get confused of so much different (and sometimes ?difficult?) explanations and start just with your last correct calculated result: 11.75 moles HCl!
As you explained that this 11.75 moles are contained in 1.00 Liter (= 1.19 kg) of final Solution, so the MolaRity is just 11.75!
(Remember: MolaRity = moles per Liter final Solution!)
But as MolaLity is defined as moles per Kilogram Solvent only your MolaLity will be = MolaRity divided by mass of solvent = 11.75 (moles/Liter) / (1.19 - 0.482) (kg/Liter) = 15.42 (moles/kg Solvent)
So the MolaRity of your reagent grad HCl is 11.75, and
the MolaLity of the same Solution is 15.42.
As the Question asks for the required mass to make a 0.1 molaR Solution you can simply calculate from your first result 1.19 kg / 11.75 moles * 0.1 moles = 0.01013 kg
Conclusion: Weight 10.13 g of your concentrated HCl into a volumetric flask of 1.0 Liter and fill with (dest.) water till to the mark! That makes 1.0 Liter with 0.10 moles HCl.
And that’s just all.