~ 지만요 : I think this is combined "지만"(But or However) + " 요"( honorific expression to talk to people, or polite way)
for example, " Learning Korean is hard, but it is fun."
Learning Korean(S) + is (V) + hard(adj), but it is fun.
한국어를 배우는 것은 어렵지만(요), 재미있어요.
Thanks and have fun to learn Korean!