Rambha is one of the most beautiful divine apsaras (damsels) in the court of Indra. There are numerous stories associated with Apsara Rambha. As per a story in the Ramayana, Rambha was the reason for a curse on Ravana due to which he could not touch Mata Sita.
Rambha was betrothed to Nalakubera, son of Vaishravana (Kuber). Vaishravana was the brother of demon king Ravana.
One day Rambha was on her way to meet Nalakubera.
Ravana happened to see her and tried to lure her into satisfying his lust.
She told him that she was going to Nalakubera, who was son of his brother and this made her his daughter-in-law.
Ravana was not ready to listen to Rambha and forcefully violated her.
A dishonored, Rambha went to Nalakubera and told him about Ravana violating her.
Nalakubera cursed Ravana that he would die if he sought to violate the chastity of another woman against her will.