"
.i ny za'u re'u pensi lo nu ta'i ma kau catra kei mu'i lo nu co'u lo nu ca'a mlerai be ro lo selgu'e cu na surla kakne ri'a lo nu jilra"
(first, I should note that on a grammatical note, genrei doesn't like it without a "boi" or "cu" between "ny" and "re'u" since they otherwise form into a single lerfu string. jboski (online jbofi'e), OTOH, has no problem with it. I"m not sure what the "correct" interpretation is according to the formal grammar)
pensi-2's are normally considered to be ideas, not events, so it should be si'o, not nu, for those who are pedantic about such stuff. But more importantly, I'm again having trouble getting the proper sense of the sentence. I think you are trying to say that she is once again thinking about how to kill (Snow White) because she is not able to relax because she is no longer the most beautiful in the land, due to her jealousy. Which I guess works, but it's real hard for me to puzzle out the convolutions of the sentence due to the nested modals and tenses
--gejyspa