彼女と結婚したい。

English Translation

I hope to marry her.

Why would you use here と instead of を?

Hi @Sersovi, welcome to the forum!

Tis is an interesting question, but as a native Italian speaker, it did not occur to me, because we commonly use a similar construct (and also one that mirrors the English version).

I think 「結婚する」may be thought as meaning “to get married”, instead of “to marry”. So using a direct object would not work (You cannot say “I want to get married her”, you have to say “I want to get married with her”).