Show them a picture of hell
If it were someone in their teens to say early 30's, here what I would say to them.
"You are still young and have only been told life is black and white by parents and elderly. So there is a lot of confusions when some aspects of life turn out not like that. It is a matter of accepting most things in life is one shade of grey or another. That is, there is a lot to experience yet by the person and one should not expect perfections. What seems unbearable is just one shade of grey and confusion one goes through. And there are heaps of life to be experienced yet..."
you can tell them you love them.
Offer them money
First thing don't get angry and yell or be hysterical. That doesn't help anyone. Doesn't matter if you are, the suicidel person needs someone to be strong not emotional. Don't judge and be careful what you say. Anything can trigger someone so avoid things you know will or might. Just talking to them is enough sometimes. Show them someone cares and wants to hear them.
The reality is that if someone is dead set gonna kill themself, the best you can do is delay them and try get them to speak to a professional. Someone will always find a way and some might even be able to lie and decieve till they can.
unfortunately I don't think you would notice the upcoming event until it was to late unless you had already been through someone else doing it. I know ididn't.
happened with a good friend, no one knew, not even family til it was over.
Would talk to him/her about myself. I experienced extreme situations and didn't committ suicide. So....it's possible to live and give meaning to everything. Tomorrow is Always another day.
don't... please, don't... *starts a new round of angry birds*
i do, once i get 3stars on everything i just reset everything
it's really a case by case sorta thing best advice I can give is try to remind person of the positives in their life