This is the 6104th most frequent Korean word.
세를
"세를" refers to "rent" or "lease" in English.
In this sentence, '세를' refers to 'rent', and is used to specify '집세', meaning 'house rent'.
나는 매년 집세를 내고 있습니다.
I pay house rent every year.
Here, '세를' indicates the concept of being rented, and modifies the verb usage in context.
이곳은 세를 주고 사용하는 시설이에요.
This place is a facility that is rented and used.
In this context, '세를' again refers to 'rent' as a subject being altered or increased.