The question is clearly referring to the story of Shakuntala and King Dushyanta, that appears in the famous Sanskrit epic Mahabharata, and which was adapted into a drama by famous 4th century Sanskrit dramatist and poet Kalidasa. This story refers to actual historical events that are supposed to have taken place many thousands of years back. It is very difficult to determine the exact elements of truth in the episode described in Mahabharata, however, it is interesting to note that one of the original names of India by which Indians described the country, and which is still the official name of the country - Bharat, is derived from the name of son of Shakuntala and Dushyanta - Bharat. The spellings of these two names in English are same, but the pronunciation in Hindi and Sanskrit are different. To get the pronunciation of the name of the country right a more appropriate spelling will be Bhaarata.
The story is fairly long and shortening it to fit the word limit of this site will take away all the charm of the story. However I will try.
Dushyanta, a king, while hunting in forest happens to meet Shakuntala, a beautiful young lady living in a hermitage in the forest. The king courts her and marries her in a simple ceremony witnessed only by friends of Shakuntala. Then Dushyanta leaves for his capital to attend to his royal duties, with the understanding that he will soon return to and take Shakuntala with him with proper ceremony.
Unfortunately, Shakuntala, lost in thoughts of Dushyanta fails to take notice of Sage Durvasa who comes visiting the hermitage. Angered by this, Durvasa puts a curse on her that the person she is thinking about will forget her completely. The only remedy to make Dushyanta remember Shakuntala and their marriage is to show him the ring that he had given to Shakuntala.
Shakuntala now must go to Dushyanta and show him the ring so that he will again remember her. But unfortunately the ring she is carrying with her fall into a river on her way to Dushyanta and cannot be retrieved. Thus when Shakuntala faces Dushyanta he is unable to recall her. All her pleadings with Dushyanta and efforts to remind him are ineffective in bringing back memories of Dushyanta.
Shakuntala has no alternative but to return. After some time the ring that fell in the river, by a series of chances is presented to Dushyanta, and he remembers all the past event forgotten by him. But it is too late by then. Dushyanta is not able to find Shakuntala, who has moved to some other place and has given birth in the meantime to a son, who is named Bharat.
Many years later when Bharat is still a child, Dushyanta happens to firs see Bharat and then meets Shakuntala. In this way they are ale happily reunited.