* ʻOʻoe he mea ʻono loa (Oh-oh-ay hay may oh-noh lo-ah) - This literally translates to "You are very delicious," which is a common way to express sweetness in Hawaiian.
* ʻOʻoe he mea aloha loa (Oh-oh-ay hay may ah-lo-ha lo-ah) - This translates to "You are very loving," which can be a more romantic way to say "you're so sweet."
* ʻOʻoe he mea maikaʻi loa (Oh-oh-ay hay may my-kai-ee lo-ah) - This translates to "You are very good," which is a more general way to express appreciation.
You can also use a more informal expression like:
* E, he ʻono ʻoe! (Ay, hay oh-noh oh-ay!) - This translates to "Hey, you're sweet!"
The best choice will depend on the context and your relationship with the person you're talking to.