The connection between Clintons and Ambanis goes back to the time when Bill Clinton was the President of the United States.
During that time, Isha Ambani's grandfather Mr. Dhirubhai Ambani held a meeting with the then President. Although, the agenda of the meeting was kept as a secret, but, that didn't stop both the powerful men from showcasing their friendship in front of the world.
In 2001, during his last visit to India as the President, Bill Clinton visited Dhirubhai Ambani's house for lunch.
From left- Mukesh Ambani, Bill Clinton, Anil Ambani. Sitting- Dhirubhai Ambani.
Apologise for the bad quality, because there are very few pictures of them on the internet.
Even after the demise of Dhirubhai Ambani, the friendship between the families stayed strong. In March 2018, when Hillary Clinton was in Mumbai for a key note speech, she spent a full day enjoying the luxuries of Mukesh Ambani's home Antilia.
An influential personality like Hillary Clinton is visiting India only for this wedding reflects that they actually have a strong connection. Now, whether its friendship or just business, I don't know.