Formal and Complimentary:
* നിങ്ങളുടെ കണ്ണുകൾ മനോഹരമാണ് (ningaLude kaNnukaL manOharamaaN) - This literally translates to "Your eyes are beautiful." It's a respectful and formal way to compliment someone's eyes.
Informal and More Affectionate:
* നിങ്ങളുടെ കണ്ണുകൾ എത്ര മനോഹരമാണ്! (ningaLude kaNnukaL ethra manOharamaaN!) - This adds emphasis and expresses greater admiration for the person's eyes.
* നീ മനോഹരമായ കണ്ണുകളുള്ളവനാണ്/വളാണ് (nee manOharamaaaya kaNnukaLuLLavanaan/vaLaaN) - This means "You have beautiful eyes" and is a more informal way to say it, used with close friends or family.
Descriptive and Poetic:
* നിങ്ങളുടെ കണ്ണുകൾ തേൻ പോലെ മനോഹരമാണ് (ningaLude kaNnukaL theen pole manOharamaaN) - This compares the eyes to honey, implying sweetness and beauty.
Ultimately, the best way to say it will depend on the context and your relationship with the person you are speaking to.