How to "choose" co-founder

I dare used not "find" but "choose".

I'm advancing new business in Vietnam.
I HAD one co-founder but now I'm looking for another co-founder.

Why?

Because I decided not to work with him.
I have some reasons to decide so but the biggest reason is that I found I can't build trust relationship with him.

Startup is very hard thing.

If we have co-founder, he/she must be very helpful for founders.
However, in lots of important scenes, we need certain judgments on business. Sometimes opinions of founder and co-founder may be different.
In such cases, we must discuss merit/demerit of each opinions and must decide the best solution. A result maybe an opinion of founder, or one of co-founder, or completely different one which they can get as a result of discussion.

When we discuss in deep, deep and deep, we need trust relationship each other because strong feeling to succeed business should be precondition of discussion. If we suspect our partner even a little, we can't "hit" our spirit to him/her when discussion.

The most important factor to choose co-founder is trust relationship in my opinion. I couldn't build it with him. So I decided. That's all.