~을/ㄹ텐데 (~eul ten-de)
2. probably should do this/that (because I’m afraid it would be bad if I don’t)
In most cases where you use ~을/ㄹ텐데 to describe a possibility, you will realise that there’s always some sort of fear or worry in the sentence. This is true for both the first and second meaning.
IN SOME WAY, ~을/ㄹ텐데 IS QUITE SIMILAR TO ~(은/ㄴ & 을/ㄹ)것 같다 BUT WITH THE ELEMENT OF WORRY AND FEAR IN THE OVERALL TONE OF THE SENTENCE.
To put in simple terms, you can think of it like “I’m afraid/worried that this will happen” for the first meaning; and “because I’m afraid/worried that this will happen, I should probably do this/that)”.
Let’s take a look at some examples so that it’d be clearer.
Examples for meaning 1: 지금 잔뜩 흐린 하늘이 보여서 나가면 비가 올텐데.
It looks like the sky is very gloomy now so (I’m afraid) it might rain when I go out.
이러난 시간부터 아무 것도 먹지 않아서 머리가 어지러울 텐데.
Since the time I woke up, I didn’t eat anything so (I’m afraid) my head might feel giddy.
Examples for meaning 2: 다들은 너무 열심히 공부하니까 나도 노력할 텐데.
All of them are studying so hard so I probably should try my best too (because I’m afraid I would fail if I don’t).
엄마와 아빠는 나 때문에 예전에부터 힘들어서 나 앞으로도 부모를 잘 봉양할 텐데.
It had been tough for my Mom and Dad since a long time ago so I probably should take good care of them in the future too (because I’m afraid I would be unfilial if I don’t).