Here the "heart" represents the speaker's thoughts and emotions. Alternate translation: "Therefore I am glad" (See: [[rc://en/ta/man/jit/figs-metonymy]])
Possible meanings are 1) the word "glory" represents the honor a person feels. Alternate translation: "I am honored to rejoice in God" or 2) the word translated "glory" really means "liver" and represents the speaker's emotions. Alternate translation: "I am rejoicing"