The blank in the sentence "Modak voravta _____ Rajkumar’s ne Diksha levanu Bhavna tahi" is typically filled with the word "Samay", referring to a Jain story. The complete sentence is:

Modak voravta Samay Rajkumar’s ne Diksha levanu Bhavna tahi.

This refers to the story where Samay Kumar, while eating modaks (a type of sweet), develops a desire for renunciation (diksha).