Connecting rooms are rooms that next to each other, with a door between them, that can be locked from both sides..actually a seperate door on each side. Adjoining rooms are rooms that can be next to each other but have no connecting doors.
So...I'm not sure what your question is. If you book two rooms, connecting or adjoining, you will pay for two rooms. Each room will be exactly like the other room...two double beds, an armoir with TV, and drawers for clothing. A table and two chairs, a vanity area with hanging clothes area, and a bath/toilet area.
I'm not sure what you meant by 'you don't pay any extra for the room but do it it's adjoining.'