Can someone please help me

[Sabertooth]

1.when ever I send one of my vassels or a guy from my court out with a small
army .they never die its like 37 to 1092 army gets wipe out but he still lives
2.how high does the number have to be so thease guy leave the fraction?
3.every time someone calls for help i help them but when i call they say not at this time.

[Ninthshadow]

I'm by no means an expert but I am pretty sure I can point out the foundations and someone else can give you the advanced details.

1. I'm willing to bet that like a lot of things in this game, the chance of them getting killed or captured is randomised. Although getting the armies wiped out ect helps the odds I do not think it will ever be a certified death sentence for your vassal/court member. Especially if they are good at combat.

2. No idea on this one but higher definately helps. Hopefully someone else can sort this out and give you an acutal number. There is an alternative: You can send your spymaster to their province to 'scheme', which will discourage them from joining a faction or encourage them to join yours. Whichever is appropriate.

3. Politics is a tricky thing. The biggest factors I know of is how much they like you and how much they like your enemy. Making sure they like you more is a big step in the right direction. Ideally they should love you and hate whoever you're fighting. This is easiest to do across the religious divide. Catholics will rarely turn down a shot at muslim counties and vice versa.

Just to point out all the ways you can make them dissappear: on their character you can usually start a plot to kill them or simply pay for it and take a chance in the diplomacy screen. That tends to work better than sending them off to battle, in my experience so far.

[Nef]

To answer 2: I'm sure I read somewhere that people are significantly less likely to join/remain in factions if their opinion of you is higher than 80, so 80 is the key figure. Having said that, I've seen people remain in factions with an opinion of me of 100 (just a couple of times), so I don't think you can ever be certain.

and for 3: yes, it mainly depends on how much they like you. Before you click the button to request help, hover mouse over it and it should show a tooltip with some green '+''s and red '-''s which give you a rough idea of how likely they are to help, and why/why not.