As a response to Christopher Marlowe's more serious "The Passionate Shepherd to his Love," Raleigh's "The Nymph's Reply to the Shepherd" debunks the shepherd's sentimental, romantic vision. So, in the first stanza, the nymph doubts the sincerity of the shepherd's proposal. Written in the subjunctive mood, the first stanza sets up the hypothetical conditions expressed in the rest of the poem.
Thus, the nymph states that
If all the world and love were young,/And truth in every shepherd's tongue
she might be urged to come and live with the shepherd. But, she doubts his sincerity, as she remarks in her biting comment about the "shepherd's tongue." The nymph, one of a class of inferior divinities of mythology, is used, interestingly, to further debunk the sentimental tone of Marlowe's poem. Even the meter--iambic tetrameter--mocks Marlowe's tone because of the words that Raleigh uses. For, although they flow in much the same manner as Marlowe's, they are decidedly less romantic than those of the idealistic "The Passionate Shepherd to His Love." For instance,
when rivers rage and rocks grow cold/And Philomel becometh dumb
is in sharp contrast to Marlowe's
By shallow river, to whose falls/Melodious birds sing madrigals.
In the end, the subjunctive mood remains because the nymph realizes that the flowers, the promises, the "belt of straw and ivy-buds" are all temporal:
But could love last and youth still breed
Had joys no date or age no need
Then these delights my mind might move
To live with thee and be thy love.