thank you Kevin for explanation.

Aftab, she means "I just know that BEcause I've started to learn urdu this week." Sometimes people shorten it to 'cuz', but really, Syifa, to avoid confusion, anytime you shorten a word, you should add an apostrophe, like "I just know that 'cause I've started to learn urdu this week." to indicate that it has been shortened.

Aftab : sorry what mean?

what's the cause?