There’s no telling
Definition 1 of 1
Pro Tip 1/3Uncertainty
Use it to express that an outcome can't be predicted with any certainty. 
He's applying for jobs, and there's no telling which company will hire him.
Pro Tip 2/3Conversational
Fits well in casual conversation more than formal writing. 
With this weather, there's no telling if we'll have the picnic.
Pro Tip 3/3No Control
Suggests a lack of control over future events or outcomes. 
With the unpredictable market, there's no telling what our profits will look like.