The phrase "much sadness" means that there is a large amount of unhappiness or sorrow.
Sentences with «much sadness»
The plight of seniors in rescue fills the hearts of rescue volunteers with so much sadness. (malinoisrescue.org)
But they are not sour people, they remember with much sadness but they are not consumed with anger and do nt live with the hate that this author expresses. (bookbrowse.com)
And that evokes much sadness in me, as I am a creature of romantic wonder. (pcgamesn.com)