I didn't know that

A: You know, she has liked you for a long time.

B: I didn't know that.

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A: You know that she has liked you for a long time.

B: I didn't know that.

I know that 'you know,' as an interjection and 'you know that S + V' have different nuance but I think that answers to the questions with different usage of 'you know' in it each could be the same like the example dialogues above. I know that the examples are so lame but could you please give me your opinions if you do not mind?

So my point is that in some contexts, although questions are different, answers could be the same like that? Please, enlighten me and thank you as usual in advance. Have a good day.