"I know that you two meet frequently."
Translation:So che voi due vi incontrate frequentemente.
Strange that Reverso uses passato remoto for "you two meet" independent of whether incontrare or conoscere is used. See: https://dictionary.reverso.net/english-italian/you%20two%20meet/forced
I think it is because in English we take it for granted that the two meet each other, - but in Italian we must make it clear who they meet.
You two frequently meet him = Voi due gli incontrate frequentemente
You two frequently meet = Eeehh . . . . chi due incontriamo spesso?
You two frequently meet each other = Voi due vi incontrate frequentemente