B1
used to emphasize what is really true, or to give more information
Dictionary examples:
She said she was a little late. In fact, the party ended yesterday! (0.0)
I thought I was good at math. In fact, 2+2=5 in my world! (0.0)
I thought I was invisible. In fact, everyone was just ignoring me! (0.0)
We met Rebecca for lunch. In fact, we spent the whole afternoon with her. (12.4)
I was told there were some tickets left but in fact they were sold out. (21.1)