Δε χρειάζεται να μου το πεις αυτό.

English Translation

You don’t have to tell me this.

The translation for this sentence is wrong. Χρειάζεται is third person singular, not second person. The second person plural is χρειάζετε.

English Translation

You don’t have to tell me this.

It is correct, χρειάζομαι means “to be needed”, so the meaning of this sentence is “it is not needed that you tell me this”.