Canto 3 -
Araṇya-kāṇḍa
Chapter 53: Sītā Chastises Rāvaṇa
Text 3.53.6

परमं खलु ते वीर्यं दृश्यते राक्षसाधम।
विश्राव्य नामधेयं हि युद्धेनास्मि जिता त्वया॥

paramaṁ khalu te vīryaṁ dṛśyate rākṣasādhama
viśrāvya nāmadheyaṁ hi yuddhenāsmi jitā tvayā

paramam = supreme; khalu = indeed; te = your; vīryam = prowess; dṛśyate = is visible [to all]; rākṣasa-adhama = O lowest of the rākṣasas; viśrāvya = after [proudly] proclaiming; nāmadheyam = your name; hi = because; yuddhena = in combat; asmi jitā = have won me; tvayā = you.

O lowest of the rākṣasas, indeed, your supreme prowess is visible [to all] because you have won me in combat after [proudly] proclaiming [your] name!

“Your supreme prowess is visible [to all]” is a statement of irony. She wants to tell him that his prowess is extremely low-class and she states the reason in the second half of the verse, which is [another] statement of irony.

[This verse can also directly mean:] “[O lowest of the rākṣasas, indeed,] your supreme lack of prowess, that is, impotency [is visible to all] because [you] have not won me in combat [after proudly proclaiming your name!]”1

1 Rāmāyaṇa-bhūṣaṇa: yadvā te paramam avīryaṁ klībatvam. hi yasmād yuddhe na jitāsmi.