Spanish speakers, be careful. Spanish version of this sentence wouldn't require the subjunctive form, but Italian does.
"Credo che tu capisca questo", but - "Creo que tú entiendes esto"
The negative sentence "No creo que" (non credo che), or for example "No pienso que" (non penso che) on the other hand would require the subjunctive in both languages.
I am confused why some subjunctive translations accept "will (insert verb" and others do not. Like in this sentence it will not accept "I believe that you WILL understand this" but in an earlier similar sentence (sorry, cannot remember the exact wording), it said "will (insert verb)" was the correct translation.