Ramayana 2.12.76

सतीं त्वामहमत्यन्तं व्यवस्याम्यसतीं सतीम्।रूपिणीं विषसंयुक्तां पीत्वेव मदिरां नरः।।।।

satīṁ tvām aham atyantaṁ vyavasyāmy asatīṁ satīm | rūpiṇīṁ viṣasaṁyuktāṁ pītv eva madirāṁ naraḥ ||

Just as a man, deceived by an alluring appearance, drinks wine mixed with poison thinking it wholesome, so too I had firmly believed you to be a chaste woman—yet in truth, despite your great beauty, you are unchaste.