Canto 3 -
Araṇya-kāṇḍa
Chapter 17: Śūrpaṇakhā Meets Rāma
Text 3.17.20

न हि तावन्मनोज्ञाङ्गी राक्षसी प्रतिभासि मे।
इह वा किन्निमित्तं त्वमागता ब्रूहि तत्त्वतः॥

na hi tāvan manojñāṅgī rākṣasī pratibhāsi me
iha vā kiṁ-nimittaṁ tvam āgatā brūhi tattvataḥ

na hi tāvat = don’t really; manojña-aṅgī = as a woman of charming bodily beauty; rākṣasī = a rākṣasī; pratibhāsi = you seem to be; me = to Me; iha = here; kim-nimittam = why; tvam = you; āgatā = did come; brūhi = speak; tattvataḥ = truthfully.

As a woman of charming bodily beauty, you don’t really seem to be a rākṣasī to Me. Speak truthfully. Why did you come here?

Because Śūrpaṇakhā had referred to the forest as rākṣasa-sevitam (“frequented by the rākṣasas”), Rāma suspected her of being a rākṣasī.1

1 Rākṣasa-sevitam appears in text 13 in this chapter.