My love is such that Rivers cannot quench, Nor ought but love from thee give recompense.
Now our lady takes a turn from wealth to nature, and describes her love in more elaborate terms.
It is so great that not even a river can "quench" it, and the only thing that can give her "recompense" is love from her husband.
The word "quench" means lots of things, which makes it tough to suss out the meaning of this line. It usually means to extinguish, put out, or satisfy. We often say, for example, "I need to quench my thirst with a glass of water." So does she mean that her love is like a giant fireball that not even a river could put out? Or does she mean that her love for her husband is so powerful that it (and she) can never be satisfied, no matter what? Of course no river is about to pour down on her sitting at her writing desk, so we'll take this to be a metaphor for anything that might (but can't) satisfy her love.
"Recompense," on the other hand, has only one meaning: compensation, or payment for something, often as payback for a wrongdoing. Based on this, it's safe to assume the speaker is suggesting that she will only be satisfied if her husband loves her in return. So at least we know there's one thing that can quench her thirsty love – her husband's reciprocation. It takes two to tango.
And before we forget, "ought" is an old word for "anything."
Thy love is such I can no way repay. The heavens reward thee manifold, I pray.
The speaker now shifts gears and starts to talk about her husband's love for her. She says she has no way of repaying him for his love, and she prays that the "heavens reward" him. This chick means business.
First, the phrase "thy love is such I can no way repay" is a way of saying "your love is so awesome that I don't know how I can ever repay you for it." You're lucky if you know that feeling!
And "Manifold" means "in many ways" or "many times." So she's hoping that, while she can't ever repay her husband, the heavens – that is, God – will.
One thing you might want to note is that the second line is in reverse order. She means "I pray [that] the heavens reward thee manifold." It makes the sentence a little wonky to read, but poets who are working in rhyme and meter often rearrange their sentences to make them fit the form they've chosen. Tricky!
Then while we live, in love let's so persevere That when we live no more, we may live ever.
The speaker concludes the poem by saying that she and her husband should love each other so strongly while they're alive that they will live forever.
(The icing on the cake is the lovely alliteration of "live, in love let's." Beautiful sounds for a beautiful idea.)
Okay, that's romantic and all, but how exactly are they going to live forever just by "persevering" in their love? Well, it's possible that the speaker means they're love will be so strong and admirable that other people will remember them and speak about them. In this way, they will "live ever." But she could also be suggesting that immortality – a life in heaven – is somehow dependent on how strongly one loves while alive.
The word "persevere" is interesting here. It's a strong word, and we tend to use it more when talking about striving against difficulties to reach a goal. So is her marriage difficult? Or does she just mean that she and her husband will stick together through whatever hardships they might face in their lives, and that as long as they remain in love, they'll be fine?
Some versions of the poem spell "persevere" as "persever." This is because, in the seventeenth century, many people pronounced the word that way. Note how that pronunciation makes the word "sever" (a word that means to break or cut off) much more audible (just like in the name Severus Snape). Plus, pronouncing it this way makes it rhyme with "ever," which is a shortened form of "forever."
What's so great about these last two lines is that they are, in a way, a new version of the first stanza's "if/then" statements. Her final "if/then"? If we love each other steadily for our whole lives, then we will be rewarded with eternal life after death. Sounds like a good deal to Shmoop.