“a certain thing” in spanish is: una cierta cosa, (it also depends on the sentence). i don’t knows if this answers your question lol, but if you have more questions about spanish lemme know. hope this helped
"a certain thing" means "algo en particular". You use it when you refer to something specific, implying that you are talking about ONE thing in particular and not in general.
translate: "cierta cosa" significa "algo en particular". Lo usa cuando se refiere a algo específico, lo que implica que está hablando de UNA cosa en particular y no en general.
