Personally I don't hear it pronounced as a 'g' now, I think it's just the phoenetics that we aren't used to ..... sometimes it used to take me quite a few 'replays' to hear correctly, it's as if my mind has been conditioned to hear incorrectly, or with a bias, due listening to and speaking British English for over 60 years. Dfficile for me sounds as if it's spelt diffichile. Hope this helps.
https://www.duolingo.com/dictionary/Italian/tanto/2967096d73af7f799f71fd29761c57c7 - in this particluar instance tanto means 'so'.
Why is it wrong? Admittedly it's a little repetitive, but the first this is the pronoun, and the second is the emphatic. So the first one is to indicate an object or concept, and the second this can mean similar to 'so'. As in 'I didn't know it was going to be this hard'
I think everything is 'tutto' not 'tanto'
In Texas, at least, "Why is it so difficult", "Why is it very difficult?", and "Why is it so very difficult?" mean exactly the same thing when no context is given. Personally, I would probably choose to say "Why is it so very difficult?" in most cases, but none of them is incorrect. Each means something is more difficult than many other things.