I totally loved this movie, and this song was the highlight for me. Sadhna was actually my mom's schoolfriend from her days in Mumbai, which is pretty cool considering she made "Jhumka Gira Re" so famous and they had that "Sadhna Haircut" with the bangs and all that was so popular in the 60s.
Love in Simla is one of those movies that grabs you because its about rooting for the underdog ... Sadhna with her glasses and her jaded view is just so cute and anti-heroine, you HAVE to love her. It was a total Cinderella story, with Sadhna living with her aunt & uncle and spoiled cousin. But vindication comes in her stealing away her cousin's rich boyfriend, HUZZAH! She couldn't have done it without her fairy grandmother, who takes away her glasses and ponytail (sorry, that's a line from Not Another Teen Movie) and gives her the famous Sadhna Cut (essentially, it's just bangs).
I remember really wanting Sadhna's character to dump the boyfriend and go out there in the world and take over ... but whatevs.
Here's the AWESOME Love Ka Matlab Hai Pyar from Love in Simla (1960):