لم تكن ... بل ...
Use this pattern to contrast one thing with another: the first part says what was not true, and the second part gives the real idea or intention. It is very useful when you want to correct expectations or emphasize a different reason. Example: "لم أكن أبحث عن هدية، بل عن وقتٍ هادئ."
لم أكن أبحث عن هدية، بل عن وقتٍ هادئ.
I was not looking for a gift, but for some quiet time.
