Most Helpful Girl
Just be nice. Whether or not she deserves it because if you are not nice, she could potentially want revenge and this could drag on for much longer than two weeks if that happens. I don't know what kind of girl she is, but it doesn't matter. If you wanna make it as easy as possible, just be polite, respectful, etc. and remember to close the door completely. Do not leave it open with words like: "In the future, you never know," or "we shouldn't date RIGHT NOW." Don't say words like "right now." Say something like "we shouldn't date." (period) Or "this isn't working out." (period) If she tries to make you change your mind, just continue to be polite NO MATTER how much you may wanna add in a little attitude. A little attitude can build like a rolling snowball after a while.
In summary, just make it a nice, clean breakup.