Valentinus Gesinski - Valentinus

The "us" on the end is suggestive it could be a Latinisation of his Polish name, rather than a spelling mistake?

The best method is to populate the data in the name fields with information that can be supported with evidence, preferably primary sources. Then put all spelling variations into the Also Known As field. That way if other users create a profile using one of the other spelling variations the software can still find the match.

I have added the variations to this profile, I leave it up to you to find documentation to cite for one spelling as opposed to the other.

A slightly more advanced method would be to use the multiple language tabs option in the edit page, currently this profile only has Default data, you could add Polish and Latin language tabs putting the Walenty in the Polish tab and Valentinus in the Latin tab.