M & K - It’s asking someone if they’d miss you if you were gone, and

It’s asking someone if they’d miss you if you were gone, and it’s the most basic way to check if they really care.

Would you miss me back? I’m asking because I need to know if you even care.

He said 'Would you miss me back?' and I knew he was trying to test my feelings.

I asked 'Would you miss me back?' and he just said 'No.' That’s all.