Hanna, I could only guess why women choose to use the internet to find the partner if they were too busy for correspondence. It seems usual for some men to already have travel arrangements made to visit in Ukraine, so they contact the women on this site asking if they can go out on dates sometime during the next few weeks (and in such cases the women join this site for this only purpose). I'm guessing the rationale for the woman is that in spite of the chance to find a marriage partner being somewhere between dismal to extremely low, why not try it and hope for the best?? 

That being said, it's my understanding that when women (and men) don't correspond for a reasonable time period prior to meeting, they won't have much interest in the correspondence after the meeting - even in cases when it seemed like everything was fine while they were dating. In fact, I still think about the first amazing Ukrainian woman I met and wonder what went wrong - and I know that there are some women here having had those same thoughts about men.

Answering your question the best that I can, it's important for me to know the woman during a short period of correspondence, to have a good feeling about her prior to the first meeting. Under ideal circumstances, then the subsequent meetings could be arranged and planned with added confidence they will result in marriage.

And don't worry, when the woman says she's busy, no explanation is necessary!  Probably, it is better to simply ask the men when they next have an opportunity to travel, and then you can decide if the man and the time span are worth an investment of your effort. 6 months writing without meeting is too excessive under any circumstance...especially when the lady has capability and willingness to communicate in English.