Istikhara for marriage

اللَّهُمَّ إِنَّكَ تَقْدِرُ وَلَا أَقْدِرُ وَتَعْلَمُ وَلَا أَعْلَمُ وَأَنْتَ عَلَّامُ الْغُيُوبِ فَإِنْ رَأَيْتَ أَنَّ فِي فُلَانَةٍ خَيْرًا لِي فِي دِينِي وَدُنْيَايَ وَآخِرَتِي فَاقْدُرْهَا لِي وَإِنْ كَانَ غَيْرُهَا خَيْرًا مِنْهَا لِي فِي دِينِي وَآخِرَتِي فَاقْدُرْهَا لِي

Allahumma innaka taqdiru wa la aqdiru wa ta'lamu wa la a'lamu wa anta 'allamul-ghuyub fa'in ra'ayta anna fi fulanatin khayran li fi dini wa dunyaya wa akhirati faqdurha li wa in kana ghayruha khayran minha li fi dini wa akhirati faqdurha li

O Allah, You have power and I have no power, and You know and I do not know, and You are the Knower of the unseen. Thus, if You see that there is good for me in so-and-so (female) concerning my religion, my worldly life, and my hereafter, then decree her for me. And if another besides her is better for me concerning my religion and my hereafter, then decree her for me.

A general supplication modelled on the Istikhāra (Ṣaḥīḥ al-Bukhārī 1162), naming the woman; not a narration from the Prophet (peace be upon him).