People Do Change Their Opinion.

I know that many people don't like tourists from Russia, Ukraine...The tourist's Their behaviours are different some other people. But However, the people coming from these in the countries may change your negative opinion about them. it.

Technically, your sentence structure is correct and understandable.  However, it would be better to express more clearly as,

I know that many of us do not like Russian or Ukrainian tourists...  They behave differently.  However, with enough contact our negative opinion about them may change as we see their positive sides as well.