The name Rina is a girl's name of Italian, Dutch, Russian origin. Rina and is often added to lists like International Variations of Katherine and discussed in our forums with posts like "Change One Letter".
From the experts:
A pan-European short form often used as a name in its own right, Rina is sister to names like Mina and Lena, popular at the end of the 19th century and showing their pretty if slight faces again. In the Netherlands, Rina itself is sometimes shortened to Rineke, as Tina may become Tineke.