Can I use "Divinity of Pride" in my mono black commander deck? If not, then what card is/similar to Divinity of Pride but is a mono black?
Can I use Divinity of Pride in a mono black commander deck?

No.

903.4. The Commander variant uses color identity to determine what cards can be in a deck with a certain commander. The color identity of a card is the color or colors of any mana symbols in that card’s mana cost or rules text, plus any colors defined by its characteristic-defining abilities (see rule 604.3) or color indicator (see rule 204).

White appears in Divinity of Pride's mana cost, so it can't be used in your mono-black Commander deck.


If not, then what card is/similar to Divinity of Pride but is a mono black?

There is no mono-black creature gaining abilities depending on having X &quot;or more life&quot;  – that's an ability associated with white.