Crossword Genius

What told you the girl would be going to a dance? (7,4)

Ross

I believe the answer is:

crystal ball

I'm a little stuck... Click here to teach me more about this clue!

'what told you the girl' is the definition.
I can't tell whether this definition defines the answer.

'would be going to a dance?' is the wordplay.
'would' becomes 'crystal' (I can't explain this - if you can you should give a lot more credence to this answer).
'be going to' means one lot of letters go next to another.
'a dance?' becomes 'ball' (ball is a kind of dance).
'crystal'+'ball'='CRYSTAL BALL'

Can you help me to learn more?

(Other definitions for crystal ball that I've seen before include "Fortuneteller's globe" , "Means of telling the future" , "Fortune-teller's essential equipment?" , "see the result first in here?" , "Glass globe" .)

I've seen this clue in the Evening Standard.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.