She use the repetition ‘I love thee.’ This sound similar to a prayer so therefore she could be praying/hoping that someday they will be able to be together
At the beginning of the poem she make reference to her love being limitless and she also reinforce this at the last line ‘I shall but love thee more after death‘
Sonnet 43 is the length of a traditional sonnet (14 lines) but doesn’t follow the traditional sonnet rhyme scheme. This poem avoid a perfect rhyme scheme. perhaps this reflect their relationship