Sonnet 43 is one of the "Sonnets from the Portuguese" that Elizabeth Barrett Browning wrote to Robert Browning before their marriage, which she presented to him on their honeymoon. In Sonnet 43, Elizabeth Barrett Browning describes her love for Robert Browning as being passionate, virtuous, pervasive, and trusting.
When she speaks of the "depth and breadth and height my soul can reach," she describes the fervency of emotion that characterizes her love. Referring to the "passion put to use in my old griefs," she declares that as deeply as she felt the losses of her loved ones who died, she now feels love for Robert just as deeply. This is a poignant thought indeed, for Elizabeth experienced the death not only of her mother, but also of her brother by drowning. It was after her brother's drowning that Elizabeth became an invalid and a recluse; it was her relationship with Robert that restored her health and inspired her to leave her father's home for good. So, passionate love for Robert replaced her passionate grief.
As Browning describes love in this sonnet, it is virtuous, reflecting both the freedom to fight for what is right and the purity of humility.
Her love pervades every corner of her existence. During both day and night--"sun and candle-light"--her love is active. It is in the littlest things that occupy her days: "every day's most quiet need." It fills the good times, the bad times, and the in-between times: "breath, smiles, tears." She expects that it will even continue into eternity, if God allows it to.
Finally, she compares her love to religious faith, implying that it has an element of deep trust. The same way she was dedicated to her Christian faith as a child, believing in it fully, so she now fully trusts herself to Robert. And though she may have given up her faith in some "lost saints," she is now able to direct that trusting love toward Robert.
In this beautiful sonnet, Elizabeth Barrett Browning describes love as fervent, honorable, all-encompassing, and confident.