Very
Very Much, Greatly
adverb
The kanji and the word are exactly the same. That means they share meanings as well.
はなはだ
Since this word is made up of a single kanji, it probably uses the kun'yomi reading. You did not learn this reading, so here's a mnemonic to help you:
If you're very tired and very giggly, you'll try to say your friend's name but start laughing right away so it ends up sounds like, "Hannah ha ha ha (はなは)."
そのようなことが事実だとすれば、甚だ遺憾である。
If that sort of thing is true, I’m very sorry.