Question

what made helen to called Boston the city of kind heart Please give answer to my question quickly

Answer 1

The people and institutions of Boston made an enormous impact on Helen Keller's life. She was introduced to her first teacher, Miss Sullivan, at Boston's Perkins School for the Blind and made her first public appearance in the 1980s speaking before groups of the city's most influential citzens.

And there are individual citizens of Boston who contributed to Helen's progress. From Helen Keller's autobiography: 

Among the many friends I made in Boston were Mr. William Endicott and his daughter. Their kindness to me was the seed from which many pleasant memories have since grown. One day we visited their beautiful home at Beverly Farms. I remember with delight how I went through their rose-garden, how their dogs, big Leo and little curly-haired Fritz with long ears, came to meet me, and how Nimrod, the swiftest of the horses, poked his nose into my hands for a pat and a lump of sugar. I also remember the beach, where for the first time I played in the sand. It was hard, smooth sand, very different from the loose, sharp sand, mingled with kelp and shells, at Brewster. Mr. Endicott told me about the great ships that came sailing by from Boston, bound for Europe. I saw him many times after that, and he was always a good friend to me; indeed, I was thinking of him when I called Boston "the City of Kind