She wants to appear perfect to everyone, but this is something only her sister knows.

My sister knew that I would always tell her the truth.

Probably she'd be surprised how much her sister already knows.

His sister doesn't know if this is a good thing or a bad one.

"My sisters and I know we are doing the right thing."

The dead man's sister obviously didn't know her brother well enough to account for all of his friends.

If the sister knows anything, I can work on her.

Even now, his parents and sister don't quite know what to make of him.

Did Mark's mother and sister know him after so long a time?

How could his sister have known, if he had left this note just last night?