My love in Russian

Russian affection is built on diminutives: the suffixes -ушк-, -оньк-, -ик turn ordinary nouns into warmth. Солнышко is the sun made small and dear; зайка is a hare made huggable. This machinery is productive, and couples invent their own.

The adjective endearments agree with who you are addressing: любимый and милый to a man, любимая and милая to a woman. The noun ones (солнышко, зайка) are gender-free and safe in both directions.