You can perform this Bismillah Wazifa for love after Isha Namaz. It does not have to be done immediately after Isha, but it must be performed sometime after Isha and before sleep. You must be in a state of Wudu while reciting the Bismillah Wazifa.

Recite the following:

فلاّن كُن فِي الحُبّ مَعِي بحق بِسْمِ اللهِ الرَّحْمٰنِ الرَّحِيْمِ

Fulan, kun fil-hubb ma‘ī bi-haqqi Bismillah hir rahman nir raheem

Replace فلاّن / Fulan with the name of the desired person you wish to fall in love with you. Recite this exactly 786 times every night, not more and not less. You can use a digital counter or a traditional Tasbeeh to keep track of the counting.

InshaAllah, within just a few days, you will see that your desired person will begin to develop strong feelings of love for you, and that person attitude will completely change towards you.