Formal:
* 저도 사랑합니다 (Jeodo saranghhamnida): This is the most formal and polite way to say it. It's suitable for someone you're not very close to, like an elder or someone in a position of authority.
Informal:
* 나도 사랑해 (nado saranghae): This is the most common and casual way to say it, suitable for friends, family, and significant others.
* 나도 좋아 (nado joa): This means "I like you too" and is a softer, less intense way to express your feelings.
More affectionate:
* 나도 너무 사랑해 (nado neomu saranghae): This means "I love you too, very much". It's a more intense way to express your love.
* 나도 너 사랑해 (nado neo saranghae): This is similar to "nado saranghae", but using "neo" (you) instead of "na" (I) makes it more personal and affectionate.
Remember:
* When speaking to someone older or in a position of authority, it's always best to use the formal form.
* You can add "요" (yo) to the end of any of these phrases to make it a bit more polite, but it's not necessary.
Choose the phrase that best suits your relationship and the situation.