Mr Mandela proposed to Amina, the widow of veteran African National Congress (ANC) activist Yusuf Cachalia, after his 27 years of imprisonment and his marriage to Winnie Mandela ended. But, she dismissed his declarations of love, she wrote in her biography 'When Hope and History Rhyme'.
Amina, who died last month aged 83, revealed an intimate and affectionate side to the relationship between her and lifelong family friend Mandela in the book released after her death.
Her children, Ghaleb and Coco Cachalia both confirmed that their mother had confided in them about Mr Mandela's marriage offer.
Mr Mandela, aged 94, is currently in a Pretoria hospital being treated for a lung infection. He was elected the first black President of the rainbow nation in 1994.
Amina and Yusuf Cachalia spent many years in India, where he headed the desk of the ANC in exile.
In her book, Amina has given vivid descriptions of private visits to her apartment by Mandela and her visits to his office and residence.
"On one of these visits I must have been looking rather flustered as I bustled about doing my chores," she wrote.
"(Mandela) sat me down on the two-seater couch in the living room and kissed me passionately. Running his fingers through my hair he said: "Do you know that you are an exceptionally beautiful, vivacious and enticing young lady?" I hollered at him. He looked very worried and wanted to know what was so wrong with what he had said. I replied gently: 'I'm not a young lady; I am a middle-aged woman'."
"He looked relieved and said: 'Okay lets begin again'." Then he repeated the string of adjectives, substituting 'old' for 'young' lady. I screamed again and said that I was not an old lady either," she revealed.
Amina recalled one evening when Mr Mandela visited her apartment in Johannesburg. She prepared crayfish for him, which he did not eat, as he was upset on being rebuffed.
"That night Nelson declared his love for me in no uncertain terms. I resisted, reminding him of his marriage (to former Mozambican First Lady Graca Machel), and the fact that while I may have been moved to consider his overtures positively, his marriage to Graca prevented me from doing so," Amina wrote.
"I was free, he was not. He was clearly upset. I had hurt his feelings and resisted his advances. I begged with him to stay for crayfish but he brushed my pleas aside and walked out of the door."
On a visit to visit to Mr Mandela's Houghton home the next day, Amina revealed how he sat opposite to her and wrote notes to her which said "beautiful, endearing things to me."
"The day before had evidently been forgotten and we were to make a fresh beginning. But I told him that we were playing with fire and I prepared to tear up the notes. He stopped me, assuring me that he would shred them once he had finished writing," Amina recalls.
"Nelson was not a great romantic figure. Perhaps the years in prison had dampened that side of him. He would express his love or feelings in a rather matter-of-fact fashion. Perhaps the closest he got to expressing his feelings was when he wrote these notes to me in the garden of his Houghton home.
"But I could not return any of his rigid gestures of love. I was not in love with Nelson. I loved him dearly and yet I could not bring myself to want him as I did Yusuf, even in our old age," Amina concludes.
Amina hailed from a family of activists. Her father, Ebrahim Asvat was a companion of Gandhi during his stay in South Africa and was chairman of the Transvaal British Indian Association, which later became the Transvaal Indian Congress.
She met her husband Yusuf when he was interviewing candidates for bursaries offered by India. Although she failed to get a passport to study in India, she married Yusuf and also became a strong leader in women's movements in South Africa, despite repeated banning orders which confined her to her home. Yusuf Cachalia died in 1995 in New Delhi.