请帮忙翻译一下:中译英

Please don't worry, I have confirmed with the agent for three times. And they promised me that they won't give this air-ticket to others.If they do, they will be persecuted.
这样写会比较地道，外国人也能看懂。

请放心，我已经和代理商确认过三次了，他们答应我不会给别人这张机票的。否则，我会杀掉他们。
Please be assured that I have already confirmed and the three agents, and they agreed to this, I will not give others the ticket. Otherwise, I will kill them.

Please rest assured， I have already confirmed with the agent for three times, they promised me not to give others this ticket. Otherwise, I will kill them.

I have confirmed with the agent for 3 times about this ticket!
They promised to me that they'll keep it for me,so don't worry about this.
If not~i'll kill them.(否则我会杀了他~~如果这句话你说给老外听~人家不吓死啊··)