This is the 14348th most frequent Turkish word.
olmanı
"Olmanı" means "your being" or "your becoming" in English.
In this context, 'olmanı' indicates a desire or wish for the subject (second person singular) to achieve or be in a specific state.
Mutlu olmanı isterim.
I wish for you to be happy.
The word 'olmanı' in this sentence refers to the state of becoming or being something, directed towards the second person singular (you).
Başarılı bir öğrenci olmanı bekliyorum.
I expect you to become a successful student.
Here, 'olmanı' signifies a suggestion or recommendation about achieving a state directed towards 'you' (second person singular).