I'm going to ask my sister for money
Can you tell me why you're asking her for money?
There is no reason. I just want the money.
You should not just ask your sister for money. You should earn the money yourself.
No, she has the money and I want it. I want her to give me the money for free.
You shouldn't expect anyone to give you money for no reason. You should discuss with your sister on how you can earn the money or borrow it with the intent to pay it back.