Standard transliteration of the English name Denise:
丹 (dān) for 'De-',
妮 (nī) for '-nee-' (a stock character for female-name syllables, also seen in
安妮 Annie),
斯 (sī) for the trailing '-s'. The pick of
妮 over phonetically-equal alternatives signals 'female name' to a Chinese reader.