I can tell you about the day I met her.
I can't tell you the day of the week or even the date, but I can tell you details.

I can tell you that she was wearing a grey hoodie and pink converse.
I can tell you that she had the most amazing smile I've ever seen.
I can tell you that she had her hair down, but brushed behind her ear,
And I can tell you that her hair is a grey-brown colour.

I can tell you about the other day when we went out to the local woods. She was wearing all black.
But she was smiling, and I can tell you that she has the cutest blush ever that starts by her nose and covers her entire face.

I could tell you all about her.
I couldn't tell you what body spray she was wearing, but I can tell you that it smelt like spring, and comfort.
I can tell you that you could search the Amazon rainforest and not find something that smelt as nice.

I could tell you all that, it just wouldn't do her justice.