與你= with you
例如：I'd like to share the cake with you.我想與你分享蛋糕
于你= 給你= to you
例如：I'd like to give the cake to you.我想把蛋糕給予（于）你.
于字還有在的意思,英語中則可以翻譯成為介詞on,at,in
例如：we have arrived at the your shop.中的at
when will we arrive in your town.中的in
于字是中文的文言字,意思較多翻譯時(shí)候應(yīng)酌情而定.希望樓主滿意!