PLEASE HELP 15 POINTS!! Complete the Spanish sentence

No seas maleducada. No te olvides de dar una propina al portero en el hotel.

Es muy importante ser un huésped __________.


A sepcific word of the lesson has to match.
These are the words that could match:

-respetuoso/respetuosa
-la cortesía

I am guessing it is respetuoso or respetuosa since la cortesía is a noun. Is it the female adjective or the male adjective though?