And this is my humble opinion, for your reference only.
個人拙見，僅供參考。
My first understanding is derived from Mr.and Mrs.Browning's background: the spiritual influence on their work. The link of Wikipedia reveals that "Much of Barrett Browning’s work carries a religious theme" and "She believed that Christ's religion is essentially poetry—poetry glorified. She explored the religious aspect in many of her poems, especially in her early work, such as the sonnets."So was her hu*****and, Mr.Browning. You can sense some hint from his work as well.
If you think the above reasoning is way too farfetched, then lets return to the general cultural background. "The other world" has always been an allusion (an overtone) of "paradise" in the occidental world. Because "love" is emphasized in the quotation, so it won't be "hell" for sure.
Then, "the other world" could be paradise, heaven, kingdom of God.........there're many many names of this paradise, where we'll become eternal.
But love is forever eternal, this world or the other world. The western culture believes that love is the powerful force that keeps us alive,even after death.
剩下的怎麽翻譯就看你了，直譯“另一個世界”還是按照曆來的習慣譯。
不過這真是個beautiful piece......I've also heard that the book fell from the shelf on its own~~很美的故事，可惜，他們在一起生活的日子還是短了些。小時候看過童話Pied Piper of Hamelin，後來才知道這是Robert Browning從民間童話故事中采集來的，嗬嗬～
Have a good night!
