Casemiro said his impending move to Manchester United is not motivated by money as he bid an emotional farewell to Real Madrid on Monday.
The Brazil midfielder, 30, said he is joining “the biggest team in the world” after a nine-year spell with Real.
United have agreed to pay up to £70m to sign Casemiro on a four-year deal which would make him one of the top earners at the three-time European champions.
“If it was about money I would have left four or five years ago,” he said.
“Those people who think that are wrong, they don’t know me at all.
“The club has always treated me very well. It’s my decision, my path.”
After joining from Sao Paulo in 2013, Casemiro helped Real win the Champions League five times, plus La Liga three times and the Cope del Rey once.
He started last season’s Champions League final, as Real beat Liverpool to become European champions for the 14th time, and he made his 336th appearance for the Spanish giants as a substitute in last week’s opening-day win at Almeria.
“I spoke to my agent after the Champions League final as I had the feeling that I was coming to the end of my cycle here,” said Casemiro.
“It was the hardest decision of my life but I’m excited about what’s ahead of me. I want to face new challenges, know a different league, a different country and a different culture.
“I’m going to the biggest team in the world, that can compete with the greatness of Real Madrid, although now it doesn’t.”
United have lost their first two games of the new Premier League season and host Liverpool at Old Trafford on Monday.