Despite the confessional tone in this sonnet, there is no direct reference to the youth. The general context, however, makes it clear that the poet's temporary alienation refers to the youth's inconstancy and betrayal, not the poet's, although coming as it does on the heels of the previous sonnet, the poet may be trying to convince himself again that "Now" he loves the youth "best." Sonnet 116, then, seems a meditative attempt to define love, independent of reciprocity, fidelity, and eternal beauty: "Love's not Time's fool, though rosy lips and cheeks / Within his bending sickle's compass come." After all his uncertainties and apologies, Sonnet 116 leaves little doubt that the poet is in love with love.
The essence of love and friendship for the poet, apparently, is reciprocity, or mutuality. In Sonnet 116, for example, the ideal relationship is referred to as "the marriage of true minds," a union that can be realized by the dedicated and faithful: "Let me not to the marriage of true minds / Admit impediments." The marriage service in the Episcopal Book of Common Prayer — "If any of you know cause or just impediment" — provides the model for the sonnet's opening lines. In them, we see the poet's attitude toward love, which he proceeds to define first negatively. He explains what love is not, and then he positively defines what it is. The "ever-fixed mark" is the traditional sea mark and guide for mariners — the North Star — whose value is inestimable although its altitude — its "height" — has been determined. Unlike physical beauty, the star is not subject to the ravages of time; nor is true love, which is not "Time's fool."
The poet then introduces the concepts of space and time, applying them to his ideal of true love: "Love alters not with his brief hours and weeks, / But bears it out even to the edge of doom." Note that the verb "alters" is lifted directly from line 3, in which the poet describes what love is not. "Bears it out" means survive; "edge of doom," Judgment Day. Finally, with absolute conviction, the poet challenges others to find him wrong in his definition: "If this be error and upon me proved, / I never writ, nor no man ever loved." Just how secure the poet is in his standards of friendship and love, which he hopes that he and the youth can achieve, is evident in this concluding couplet; he stakes his own poetry as his wager that love is all he has described it to be.