verb + ~야 + clause, 야 conjugation
This is something that seems fundamental to Korean grammar but i have seen almost no information on the topic. Usually when you use 야 conjugation for verbs, it is followed by 하다 / 되다 ... for example 밥 먹어야 돼요, 공부 열심히 해야해요, etc.

However, I have discovered through texting and reading that there is a whole other world where, instead of 하다 / 되다, the phrase after the 야 verb can contain an entire clause. For example, 어떻게 해야 맘을 풀어주지? (i also saw that phrase but i don't know what it means, if someone could translate that would be great!)

I'm curious about what is the meaning of the sentence if you have this structure with a 야 conjugated verb and an entire clause / phrase afterword. I'm also curious what the above phrase can be translated to :)

Question

verb + ~야 + clause, 야 conjugation
This is something that seems fundamental to Korean grammar but i have seen almost no information on the topic. Usually when you use 야 conjugation for verbs, it is followed by 하다 / 되다 ... for example 밥 먹어야 돼요, 공부 열심히 해야해요, etc.

However, I have discovered through texting and reading that there is a whole other world where, instead of 하다 / 되다, the phrase after the 야 verb can contain an entire clause. For example, 어떻게 해야 맘을 풀어주지? (i also saw that phrase but i don't know what it means, if someone could translate that would be great!)

I'm curious about what is the meaning of the sentence if you have this structure with a 야 conjugated verb and an entire clause / phrase afterword. I'm also curious what the above phrase can be translated to :)

Answer

어떻게 하다. means below.
1. do(or manage) by some means or other,
2. take some measure,
3. do(or manage) somehow,
4. manage to do

어떻게 해야(하여야) 하다. means
should do(or should manage) by some means or other,
must do(or should manage) by some means or other.

문장(sentence)의 주어(subject). 목적어(object) 생략(skip or omit).
hmm....this is very difficult even though native korean.
so,  you should guess that,  including whole sentences and paragraph.

어떻게 해야 그녀의 맘을 풀어주지?
(내가) 어떻게 해야 그녀의 맘을 풀어주지?
(내가) 어떻게 해야(하여야) 그녀의 맘을 풀어주지?
----
for example.
(내가) 어떻게 해야 (그녀의) 맘을 풀어주지?
What should i do to change her's mind into good mood? (is it ok??)
----

한국어 문법의 가장 어려운 부분중의 하나이고, 게다가 영어로 작문을 해야한다니....아.... 정말 어렵네요.

(누가) (무엇을) 어떻게 해야 (누구의) 마음을 풀어주지?
(누가) (무엇을) 어떻게 하면 (누구의) 마음이 풀리지?

(누구의) 마음을 풀어주려면 (누가) (무엇을) 어떻게 해야 하지?
(누구의) 마음이 풀리려면 (누가) (무엇을 ) 어떻게 해야 하지?

Answer

어떻게 해야 맘을 풀어주지?
맘 = 마음(shortened) 
맘을 풀어주다 - soothe you/him/her etc.
어떻게 해야 맘을 풀어주지? = 맘을 풀어주려면 어떻게 해야하지?
What should I do to soothe you/her/him etc.
or What do I have to do to soothe you/her/him etc.
밥 먹어야 돼요 - I have to eat rice.
공부 열심히 해야 돼요 - I have to study hard.
~해야 돼/~해야 해 is close to have to do something
~해야지 is close to should