how did duncan and courtny get to Liebe each other because I dont get it.

Like old people say, Opposites attract. Duncan and Courtney are one of those Love/Hate relationships. Mostly, Courtney does the hating. Courtney is one of those 'Good-Girl-Gone-Bad' types. She even stated that "Danger is...kinda HOT." She's attracted to bad boys, i.e. Duncan, but she doesn't want to admit it because she has built up this reputation that she's absolutly perfect in every which way. I think Duncan likes her 'cause he thinks she's hot and he has created a monster. But in the end, I truley think that both Liebe each other, even if Courtney may never admit it. XD

That's exsactly what happened in "The very last episode really".