To one who pronounces his love for you, for Allah’s sake1 du'a

May He for Whose sake you love me, love you.

Reference:Abu Dawud 4/333. Al-Albani graded it good in Sahih Abu Dawud 3/965.Hisnul Muslim 200

أَحَبَّـكَ الّذي أَحْبَبْـتَني لَه

Transliteration

Aḥabbaka ‘lladhī aḥbabtanī lah.

Translation

May He for Whose sake you love me, love you.