Just considering the title the reader understands the sonnet it is a part of a collection because the title bears the same first line of sonnet; the reader can think the poetry deals with love. The speaking voice says her man might love her for a part of his body, but he must love him for just love. Love is eternal while her smile, her eyes, her voice, her thoughts are mortal things and they will finish. Of course the man was fall in love also for these things, but the time will change them or the way to see them. The speaking voice says he doesn't love her when she cries, because the love transforms into pity.
The sonnet deals with the concept of courteous love.
The first quatrain introduces a dialogue between poetess and her lover. The speaking voice does an invitation to him to love her "only" for her intelligent and not for her approach to him.
She uses words as ‘'smile", "look", "way of speaking" and they indicate actions and the way she approaches to him.
In all sonnet the speaking voice invites her man to love her for true feelings because when she will become old he probably won't like her smile or her eyes, her body is a mortal thing but her soul and mind will be the same ones forever. The sonnet follows the typical Elizabethan model sonnet, indeed it is organized into 3 quatrains and the couplet.
In the sonnet the poet uses the long vowel sound of ‘'a'', ‘'y'' and ‘'I'' in the words "sake, say, I, smile, way, mine, day, may, changed, change, may, dry, thy, thereby, sake, may" to give a sense of distance between the speaking voice and the mortal things.
The speaking voice asks to his lover to love her for the only eternal thing she has: her soul.