You can use the phrase Mahal kita with almost anyone -- from your grandmother to your lovey-dovey. But if you want something dramatic for a special someone, use Iniibig kita.
Mahal na mahal kita.
I love you very, very much.
Mahal kita talaga.
I really love you.
Mahal din kita.
I love you too.
Mahal mo ba ako?
Do you love me?
Oo, mahal kita.
Yes, I love you.
Mahal kita sobra.
I love you overly.