Shakespeare's Sonnets: When my love swears that she is made of truth

When my love swears that she is made of truth,I do believe her, though I know she lies,That she might think me some untutor'd youth,Unlearnèd in the world's false subtleties.Thus vainly thinking that she thinks me young,Although she knows my days are past the best,Simply I credit her false-speaking tongue.On both sides thus is simple truth suppress't.But wherefore says she not she is unjust?And wherefore say not I that I am old?O love's best habit is in seeming trust,And age in love, loves not to have years told. Therefore I lie with her, and she with me, And in our faults by lies we flattered be.