Family members have been in dispute over the reburial of the bodies of three of Mr Mandela's children.
Ndileka Mandela was speaking to the BBC on the eve of Mr Mandela's 95th birthday.
She also described how difficult it had been for the family to cope with his critical illness.
The dispute has pitted 16 members of the Mandela family, including his wife Graca Machel, and local chiefs against Mr Mandela's eldest grandson and traditional tribal chief, Mandla.
They went to the Mthatha High Court on 3 July to force the remains of three of Mr Mandela's children to be exhumed and returned to his home in Qunu, in Eastern Cape province.
Mandla had moved them two years ago to his homestead in Mvezo, 22km (14 miles) from Qunu, apparently without consulting the rest of the family and elders of the AbaThembu royal house, of which Mr Mandela is a member.
"Blood is thicker than water” Ndileka Mandela
An affidavit filed with the court alleged that Mandla had relocated the graves to ensure that Nelson Mandela would be buried in Mvezo.
The remains, now reburied in Qunu, are of Makgatho Mandela, Mandla's father who died from Aids-related diseases in 2005; Thembekile, who was killed in a car accident in 1969 and was the father of Ndileka Mandela; and Makaziwe, Nelson Mandela's first daughter who died when she was nine months old.
Ndileka Mandela said the argument over the graves was unfortunate but would not split the family as "blood is thicker than water".
"It was something that we did not want to take in the public space but because of who we are it was, it did spill over to the public space," she said.
"There is no way that I can never forgive but it's just that right now I'm still hurting."
Ndileka Mandela, an intensive care nurse by training, also complained at the intrusive nature of media questioning since Mr Mandela was admitted to hospital with a recurring lung infection on 8 June.
She said relatives had been asked "Is it over with Mr Mandela?" and "Is he on life support?"
The dispute has become increasingly bitter, with Mandla accusing some individuals of "jumping on the Mandela bandwagon" and "trying to sow divisions and destruction" in the family.