How to say "I think" if there is more than one sentence.

Question

So usually when saying 'I think' you use 'と思います' but that is normally used with a single sentence like '美味しかったと思います。' But how do you say 'I think' when you have multiple sentences? For example I am trying to say.

'Is marriage or work more important for them?' If marriage is more important, they should get married. If work is more important, they should not get married and work, I think.'

I have got this so far (I know that it is very bad so I'm sorry about it, I haven't done many constructions like this before.)

この人のために、結婚か仕事は一番大切ですか。結婚は一番大切なら、結婚します。仕事は一番大切なら、結婚をしませんしはたらきます。

(I'm sorry I know this paragraph is a grammatical mess.) I am answering a question so I would like to add 'I think' so it doesn't sound like I am saying she should do this for certain.

Answer 1

how do you say 'I think' when you have multiple sentences?

I think you could say 「～～て形、～～終止形 + べきだ + と思う」, as in...

その人にとって、結婚と仕事のどちらが（より）大切ですか。
結婚が（より）大切なら結婚して、仕事が（より）大切なら結婚｛しないで/せずに｝働くべきだと思います。

You could also use [大事]{だいじ} or [重要]{じゅうよう} instead of 大切.

or...

その人にとって、結婚と仕事のどちら（の[方]{ほう}）が大事ですか。
結婚（の方）が大事なら結婚して、仕事（の方）が大事なら結婚｛しないで/せずに｝働くべきだと思います。

Answer 2

You would still use 思う in this case. Your translation has some problem though. First, you can't use ために like that, here I would use には. Second, you should use その.

その人には、結婚と仕事のどちらが一番重要なことですか。

You don't need to repeat 一番大切 in the following part of your sentence.

結婚なら結婚するべきで、仕事なら一生独身にして働くべきだということを、私は思う。

I can't vouch that my phrases are perfectly natural but I can tell you for sure that in this case too, you would use nothing more than 思う but you should glue your sentence together.