In English, the adverb "deceptively" used to qualify an adjective raises a red flag, as its interpretation is heavily context-dependent. For instance:
Guessing how to pronounce anglicisms in French is deceptively easy.
For some people, this sentence means: "It’s anything but easy despite its apparent easiness".
While for others: "Despite appearances to the contrary, it’s actually easy".
I, for one, lean towards the former interpretation. I see some French speakers suggest the use of « d'une simplicité trompeuse », « trompeusement simple », or « faussement simple », but I’m not sure if they truly sound idiomatic to express the idea of "deceptively easy".
Personally, I want to say (at the risk of sounding somewhat verbose):
L’ennui, c'est que la prononciation des anglicismes n’est pas forcément aussi évidente qu'elle n'en a l'air.