The Spain international is set to leave Sevilla - a club he has graced for his entire career to date - for the Premier League.
Navas has struggled with homesickness in the past, passing up the chance to taste Euro 2008 success with his country, but is confident he can handle life in England.
Begiristain has no fears regarding the talented winger, with Navas now 27 years of age and under no illusions as to what he will have to contend with on and off the pitch in Manchester.
"I did not want to be anything but straight with him when we first spoke," said City's sporting director, who helped to make Navas the first high-profile signing of what is shaping up to be a busy summer at the Etihad Stadium.
"I told him about the rain and I told him about the need to learn English.
"I told him how far away from home he was going to feel. I could not have pictured a more grim picture. I had to be sure.
"But to everything I said the response was the same - more excitement and enthusiasm for the challenge.
"He is an absolute gift for us. He goes past people and stretches teams. He will give us something we don't have."