Phrases Wise People Say Instead Saying "I Don't Know" as per Psychology 

"That’s an interesting question! Let me think about it."

"I don’t have the answer right now, but I’d love to explore it further." 

"That’s a great question! What do you think?" 

"I’ll find out and get back to you."

"I’m still learning about this, but I can research and share my thoughts later!"