Phrases with "swear"
A: I swear I won't tell anyone. If I break my swear, I'm willing to suffer.
B: Great.
(later on)
B: You told everyone! You will repent when your swear comes true.

1. Does it sound natural to say "break my swear" and "your swear comes true".?
2. What structure do you usually put after "If I break my swear"? Do the following all sound natural?

- If I break my swear, I hope I will suffer.
- If I break my swear, I will suffer.
- If I break my swear, I'm willing to suffer.

Thank you.

Question

Phrases with "swear"
A: I swear I won't tell anyone. If I break my swear, I'm willing to suffer. 
B: Great.
(later on)
B: You told everyone! You will repent when your swear comes true.

1. Does it sound natural to say "break my swear" and "your swear comes true".? 
2. What structure do you usually put after "If I break my swear"? Do the following all sound natural?

- If I break my swear, I hope I will suffer. 
- If I break my swear, I will suffer.
- If I break my swear, I'm willing to suffer.

Thank you.

Answer

“If I break my swear” is not correct.  You can say “If I break my word,”. “If I break my oath,” or “If I break my promise.”    “If I break my oath, I hope I will suffer” means “If I break my oath, I deserve to suffer and so I hope that I will because that is morally right.”  “If I break my oath, I will suffer” is just a factual prediction — that is, something bad will happen to you — rather than a moral statement.

Answer

The only phrase that sounds natural is “I swear I won’t tell anyone.”

Answer

I have never used any of these expressions after the "I swear ..."