You are absolutely right. Gopi is pure at heart. She doesn't see anything bad in people. I think she felt an affinity With Anita, the moment she heard at her wedding that she was an orphan. She knows how it is when you have no one to love you or support you.
Now, she heard how she loved Ahemji. She saw her crying and she probably remembered how she struggled during her first year for Ahemji's love and in her mind she is still struggling. Since Ahemji told Anita in plain words that he hates her, Gopi feels sorry for her. At least Gopi now has a family and Anita is all alone. Gopi never thinks about herself, but feels others' pain deeply. That's why when Ahemji apologized to her and said that Anita tried to hurt her, she dismissed it and showed concern for Anita instead. Not only Gopi will never try to hurt another person, but she wil want to take on hurts of others even if these people don't deserve it.