닮다 is resembling someone or something. Four of these lines are the same saying, 사랑하면 닮는다 — 'when you love someone you start to look like them' — used about couples and long-married people, and one line varies it as 좋아하면 닮는다고. The other lines use it plainly: 그 열매를 보면 닮았죠, 'look at the fruit and you can see the resemblance'.