Sonnets are generally subjective poems, revealing some of the character traits of the sonneteer. Elizabeth Barrett Browning’s ‘If Thou Must Love Me’ is not an exception. The poet-speaker is very serious about her relationship with the lover. In the light of a patriarchal society in the Victorian era, she is uncommonly bold and radically assertive. She demands genuine and sincere love from her lover Robert Browning. And the very expression ‘If thou must love me’ suggests how determined she is. If the lover has to love her at all, he must follow her conditions. This is quite extraordinary, as women generally tend to be submissive and meek in the male-dominated society. Not to miss, she is also a passionate lover and love-seeker who wants to love and be loved unconditionally ‘through love’s eternity’.

Theoretically her conditions are justifiable, as the transitory reasons like her look or smile may make their love short-lived. So, they should love each-other unconditionally. But, in reality, we are mortal human beings. So, it is rather realistic to fall in love for one’s look or smile. It’s idealistic and difficult to love someone without a real reason.

Jayanta’s answer given above is perfectly answered to the question, excepting I’d disagree with the last lines saying it’s ‘difficult to love someone without a reason’ It conveys a wrong message plus a little contradictory

I feel it does make sense, (Jayanta’s last line) as even though it is a bit contradictory, it is the truth of life.