(私はあなたに watashi wa anatani)
償います tsugunai masu.
埋め合わせをします umeawase o shimasu.
お返しをします okaeshi o shimasu.
...etc. They are used differently in situations. You can omit the first phrase (watashi wa anatani). A naked verb will do in Japanese.
I think
借りは返すよ kari wa kaesu yo.
is most suitable between male-male relations.