The "heart" was associated with emotions. The Edomites' pride caused them to be deceived about their security. Alternate translation: "Your pride has deceived you" or "Your pride causes you think you are safe" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Here "in your heart" is an idiom that means "to yourself." Alternate translation: "say to yourselves" or "think" (See: [[rc://en/ta/man/translate/figs-idiom]])
This question expresses that the Edomites were proud and felt safe. Alternate translation: "No one can bring me down to the ground." or "I am safe from all attackers." (See: [[rc://en/ta/man/translate/figs-rquestion]])