How do you solve the partner issue?

what IS the partner issue?

well, it is the constant issue i have of that you have an idea, but you cant bring EVERYthing thats necessary to the table to get this going, in my example a designer.

i dont know any one who can do what i need, so i have to go to my best friend to get someone; the internet

so i put out ads, look at other peoples ads, and find some people. but there are constant issues that keep recurring:

1) i have to keep repeating and repeating my startup idea, because who would join a startup before they know what it is? but, i don feel uncomfortable telling someone my idea, because whats stopping them from stealing it? and then i just more and more people.

2) who says they can do what they day? for example, someone told me he can do:

Graphic interface design,

User experience,

Branding,

Product development,

SEO,

SEM,

Social Media,

Marketing and promotion.

fine, designing i can ask for links and stuff like that, but how do i ask him to show off his other stuff?

3) how do we know we will be a good fit? after reading many a HN article, ive learned that its 90% in the founders, whose to say that me and this partner i find on the internet will be a perfect match? and if not, then the startup will just crash and burn....