My true love hath my heart, and I have his,
By just exchange one for the other given:
I hold his dear, and mine he cannot miss;
There never was a bargain better driven.
His heart in me keeps me and him in one …
So begins this poem, taken from Sidney's much longer prose work the Arcadia. It is one of the finest Elizabethan love poems, and also an early example of the English or 'Shakespearean' sonnet. The speaker of the poem is a shepherdess, pledging her love for her betrothed, a shepherd who rests in her lap.
The speaker states that she and her lover have pledged their hearts to each other, and it's the best exchange or 'bargain' that could have been contrived. By exchanging their hearts with each other and pledging themselves to the other, the two lovers guide each other and make them two hearts in one.
The shepherdess tells her that her lover's heart was 'wounded' when he saw her, because Cupid, the Roman god of love, shot him with his arrow and afflicted him with love for the shepherdess. When the shepherdess saw that her love was wounded with love for her, she fell for him.