I.
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,
Unskilful in the world's false forgeries,
Thus vainly thinking that she thinks me young,
Although I know my years be past the best,
I smiling credit her false-speaking tongue,
Compare this to line four of  Sonnet 138 : 
 Unlearned in the world’s false subtleties.
The Passionate Pilgrim: 1