This is the 921st most frequent Hungarian word.
abban
"In that."
Here, 'abban' is used to describe 'az intézményben,' indicating location in a specific place.
Segíts nekem eljutni abban az intézményben.
Help me get to that institution.
In this usage, 'abban' refers to the abstract concept of 'reménykedtem,' specifying the object of hope.
Abban reménykedtem, hogy sikerül a vizsga.
I was hoping that the exam would be successful.
In this sentence, 'abban' is used as a demonstrative pronoun in the inessive case, referring to 'városban' ('in the city').