وَأَنْ تَهَبَ لِي يَقِيناً تُبَاشِرُ بِهِ…
Source: Source: duas.org · ramadan-dua-daytime-daily
wa an tahaba li yaqinan tubashiru bihi qalbi wa imanan la yashubuhu shakkun wa ridan bima qasamta li wa atini fi alddunya hasanatan wa fi al-akhirati hasanatan wa qini `adhaba alnnari wa in lam takun qadayta fi hadhihi allaylati tanazzala almala'ikati walrruhi fiha fa-akhkhirni ila dhalika warzuqni fiha dhikraka wa shukraka wa ta`ataka wa husna `ibadatika wa salli `ala muhammadin wa ali muhammadin bi-afdali salawatika ya arhama alrrahimina
grant me conviction with which You fill in my heart, faith free of doubt, satisfaction with that which You decide for me, grant me good in this worldly life and good in the Next World, and save me from the Fire of Hell. And if You have not decided at this night, during which the angels and the Holy Spirit are allowed to descend, then (please) postpone Your decisions about me to that night, confer upon me during it with remembering You, showing gratitude to You, doing acts of obedience to You, and worshipping You in the best manner. And (please) bless Muhammad and the Household of Muhammad with Your most favorable blessings, O most Merciful of all those who show mercy!
Reference / Source
Source: duas.org · ramadan-dua-daytime-daily