Formal:
* "Eu amo agora e para sempre." (This is the most literal translation and quite formal)
* "Eu amo-te agora e eternamente." (This is a more poetic and formal option, using the formal "te" instead of "você")
Informal:
* "Eu te amo agora e para sempre." (This is the most common and informal way to say it)
* "Eu amo você agora e para sempre." (This is another informal option, using "você" instead of "te")
* "Eu te amo para sempre." (This is a shorter and more direct version, focusing on the "forever" aspect)
More romantic options:
* "Meu amor, te amo eternamente." (This adds "my love" to the phrase, making it more romantic)
* "O meu amor por ti é eterno." (This translates to "My love for you is eternal", and is a very poetic option)
Ultimately, the best way to say it depends on the context and your relationship with the person you are speaking to.