What is the meaning of the line ''I love thee with a love I seemed to lose'' in Sonnet 43?
The line you’ve quoted in your question is only a portion of a thought; it would help to consider it in full: “I love thee with a love I seemed to lose / With my lost saints.” The line is in keeping with the rest of the sonnet, which expounds upon the full extent of the speaker’s love for the object of the poem. In the lines immediately preceding the one in question, the speaker states, “I love thee with the passion put to use . . . with my childhood’s faith.” The speaker’s childhood faith is pure, wholesome, and total, and it is this intense, innocent love that the speaker feels. The simple, honest passion that characterized her religious faith is the same that characterized her love for the saints as a child. The speaker assumed this saintly love to have been lost over the years as her innocence dissolved into maturity, but this feeling has been rekindled by the object of her desire. And so she loves him with this same wholesome love that she felt for the saints when she was a child, enamored with the stories of her faith.