Go for Bali,it's the best for the budget, do not miss nusa penida . Or Thailand, specifically Phuket and Krabi. Best for honeymoon. a tour of 6 to 8 days
March is not the best month to plan a trip to Europe, especially around the Alps. Try Southern Europe - Spain could be a good choice. If you're a beach person, cover Singapore & Bali (you'll get the best of both city life and laid back holiday vibe).
I would suggest you go to Krabi. There's a private beach resort called Centara Grand. it has a beautiful approach and is completely secluded and has a beautiful white sand beach.