Please tell me the difference between these two items.

Your comment is off-topic.

We crossed paths many times, but we never ended up meeting.

He and I are brothers from different fathers.

She is my uterine sister.

He is under the misconception that he understands everything.

He mistook me for my sister.

He was born as an illegitimate child and experienced many difficulties.

My grandfather used to till his privately-owned rice field.

Using the private railway makes commuting very convenient.