This is by far the easiest way to divide a room and the best way to increase the adoptability. Simply fix a pole or a beam on an elevated point of two walls. This will help you in drawing the curtain that will be hanged using pins or rings. The curtains can be cheap ready-made curtains or hand-made.
Leave a TV or radio on (fairly loud) and keep the windows and curtains closed. If possible, turn on all the lights-that way there is less chance of her noticing something is happening outside.
If you have standard sized windows then you can often buy ready made curtains more cheaply than having them custom curtains made to fit your windows. Ready mades are available in many great design so you are likely to find something you like especially if you shop around.
You will not have to stick them out like you would if a designer makes them for you. Even if the curtains a designer makes for you tende vetrate panoramiche are very pretty, but you would not like them if they are not exactly what you actually wanted. However, since you paid an insanely exorbitant price for them, you will be bound to hang them in your room even if you don't like them at all, buying readymade panoramic glass curtains saves you a lot of time.
If you would like to take advantage of the insulating advantages that some curtains offer, then to make draw curtains a more formal presentation, you could combine a valance over the top edge of your curtains to complete the look.
When purchasing made to measure curtains there are several other factors to consider. The first is how long do you want the curtain? Sill length? Floor length? Floor to ceiling? Or perhaps you are using a cornice or a valence with your curtains. This will determine the length but keep in mind...that is your preference so be sure you know the look you are going for. Designers will buy curtains that are wider than the actual window itself to make it look more substantial in the room.