John Gill Commentary 1 Samuel 10:15

"And Saul`s uncle said, Tell me, I pray thee, what Samuel said unto you." — 1 Samuel 10:15 (ASV)

And Saul's uncle said

On hearing he had been with Samuel, and perceiving so great an alteration in Saul, perhaps he began to suspect something about the kingdom; it being what everyone was talking of, and expecting every day to hear from Samuel who should be king, according to the Lord's appointment:

tell me, I pray you, what Samuel said to you ;

the earnestness with which he put this question seems to confirm the above conjecture.