Spanish phrase
Te lo contaré luego.
Meaning
I'll tell you later.
When to use it
It means the speaker will tell someone later. It promises information at a later time and can delay an answer politely.
Example dialogue
¿Qué tienes en la caja?
What do you have in the box?
Es un secreto. Te lo contaré luego.
It's a secret. I'll tell you later.