"Raj is very sad."
Translation:राज बहुत दुखी है।
This adjective has only one form. It doesn't change according to gender and number. Coincidentally it ends in ई, which is the feminine ending for adjectives that do change. But दुखी always stays in this form, independently of gender and number.
How do I know there is only one form of an adjective? Just a matter of remembering? Or is there some rule?