"That is easy."
Translation:Das ist einfach.
I know this has been a comment for years now, but I just wanted to add that I recognized "Einfach" from a song by Johannes Oerding called "Einfach Nur Weg [Just Away]". The main line says "Wo einfach alles einfach ist," which translates to "Where everything is easy." Literally, though, would this technically be "Where simply everything is easy"? Or is it just repetition for emphasis, like "Where everything, everything is easy"? Could it be both?
Use "Das" for the definite article "the" or the pronoun "that".
Use "Dass" for the subordinating conjunction "that".
"Das ist ein Buch." (That is a book.) "Das Auto ist rot." (The car is red.)
"Ich mag, dass du hier bist." (I like that you are here.)
In this sentence "That is easy" we will use the pronoun "Das".
Das is a pronoun or article meaning "this", "that" or "the", while diese is an adjective meaning "this [thing]".
Das ist ein Mann. / Das ist ein Kind.
Das ist eine Frau. / Das sind Leute.
Ich mag das.
dieser Hund / dieses Mädchen / diese Frau / diese Leute
Ich mag diesen Kuchen.
In other words, use diese when the "this" is attached to the thing it's describing (as opposed to there being a verb or something between them).
I'm guessing the alternate meanings are probably dependent upon context. Personally, I think it's pretty obvious when someone is choosing to either comment on a woman's weight or shame her for her sexuality, but that's just me.