"[Kim] knew I was eventually going to ask her to marry me," the fashion designer said. "I just had to get that ring right.
"I worked with four different jewellers. Three rings were made and only one hit the ringer and that was Lorraine [Schwartz]'s.
"I actually changed the ring the night before. The ring was less than four hours old when I gave it to her."
The Atlanta-born star said he chose to pop the question in the baseball stadium because he thought "it would be dope". He said the proposal had gone to plan aside from the lights which were not "exactly how I wanted them to be."
Kanye also hinted at what kind of wedding they might have.
"Two words: 'fighter jets'," he said when asked for a hint about the nuptials, suggesting an extravagant affair.
The father-of-one repeatedly referred to Kim as his wife in the interview on Big Boy's Neighbourhood on Monday.
Kanye also spoke of his patience waiting for Kim who has been married twice previously, most famously to Kris Humphries for 72 days.
"I had to wait through a bunch of other relationships to finally get the chance,' he said, adding he purchased a mobile phone for the first time in three years to communicate with his future wife after she split from basketball star Kris.