न नूनं बुध्यसे रामं महावीर्यं गुणोन्नतम्।
अयुक्तचारश्चपलो महेन्द्रवरुणोपमम्॥
na nūnaṁ budhyase rāmaṁ mahā-vīryaṁ guṇonnatam
ayukta-cāraś capalo mahendra-varuṇopamam
na = not; nūnam = certainly; budhyase = you do understand; rāmam = Rāma; mahā-vīryam = whose prowess is great; guṇa-unnatam = He is exalted in attributes; ayukta-cāraḥ = you haven’t employed spies; capalaḥ = and are whimsical; mahā-indra-varuṇa-upamam = and comparable to the great Indra and Varuṇa.
You haven’t employed spies and are whimsical. You certainly do not understand Rāma whose prowess is great. He is exalted in attributes and comparable to the great Indra and Varuṇa.1
1 In other words, Mārīca wanted to tell Rāvaṇa that Śrī Rāma is not a mere human being who can be casually dealt with, as per Rāvaṇa’s plans.
1 Rāvaṇa blindly believed in the words of a woman without even counterchecking it with information from his intelligence agents. Therefore, Mārīca correctly points out that he was whimsical.
Ayukta-cāraś capalaḥ also indicates that Rāvaṇa was whimsical and therefore he hadn’t employed spies. Consequently, he didn’t properly gather [sufficient] information [about Lord Rāma’s] prowess.1
Since [Rāvaṇa] set out [from Laṅkā and] returned [to see Mārīca] on that very day, Mārīca ascertained that Rāvaṇa would not listen to his words [of advice]. Therefore, from the next verse, he describes the disasters that could come about due to Rāvaṇa’s whims.