Frenkie de Jong concedes he had doubts when first joining Barcelona last summer.
The former Ajax midfielder made the move after committing to the deal in February.
De Jong said, "Many people doubted that I had made the right choice? I agree with them.
"Bara is at a different level than Ajax. You must always wait and see if you will succeed right away, with so many great players around you. So I understand people who have doubted for months.
"There are no guarantees."
