Well, Tarpi was referring more to Dina's upbringing and the inner strength and stubbornness that she was taught
He also said that she is extremely hard-working.
edit (again): I have found an interview with Dinara herself and indeed she gives a lot of credit to Zeljco for her success
Last year in Doha, while walking around with Zeljco, they saw a really fancy car and Dina told him that, when she wins a GS she'll buy him one of those
He replayed that this moment is not far away
"My dream is to win a Grand Slam, and I will win it".