Is the -니 ending always a question marker? If not, what is its purpose?
I now understand who can use -니, but was curious if it's always a question marker. If it doesn't have a question mark at the end, is it still a question? I sometimes see a question mark after 니 and sometimes don't see any question marks. What does this mean? Is it just a statement without a question mark?
e.g.
- 내 말이 니말과 다르니
- 화가나니
- 넌 누굴 사랑하니?

Question

Is the -니 ending always a question marker? If not, what is its purpose?
I now understand who can use -니, but was curious if it's always a question marker. If it doesn't have a question mark at the end, is it still a question? I sometimes see a question mark after 니 and sometimes don't see any question marks. What does this mean? Is it just a statement without a question mark?
e.g. 
- 내 말이 니말과 다르니
- 화가나니
- 넌 누굴 사랑하니?

Answer

There are many usages of "니" but it is the most commonly used as a question marker and a conjunctive particle. I would say if a sentence ends with "니", it is a question marker in almost a hundred percent of cases. However, if another clause comes after "니", it is a conjunctive particle.

봄이 오니 꽃이 핀다. Spring came, then flowers are blooming.
서울에 도착하니 7시였다. When I arrived at Seoul, it was 7 o'clock.

If you have seen any other examples that don't fall under these usages, please let me know. I will explain again.

Answer

*visualize

Answer

To vistualize the falling tone, the context decides whether it's a question or not.