English translation is
"Let those who have never loved love now; Let those who have loved love again. "
or
["Let those who have never loved love tomorrow, and let those who have loved love tomorrow." ]
Anyway, it probably means that whether you have loved or not, you must learn to love (starting from tomorrow) ~
And ... Nunquam seems to be numquam.
Actually, you can search (in Google) ~
The name of this poem is PERVIGILIUM VENERIS (the vigil of Venus in English).
You can find the English version of Wikipedia and enter the entry of PERVIGILIUM VENERIS.
Then in the external link
Choose to click on one of the provided translations, which is about the English translation of poems (jumping).
Or click pervigilium veneris, which is a book about poetry and Latin original works.
My level is limited. . Can't translate
But referring to the sentence you asked, it is the reflection that keeps appearing in poetry and is used as a section of poetry.
This poem describes a three-day holiday.
It's so complicated ~ how did you find this sentence ~