(See for example, the difference between the series, which is very close to a Visual Novel style of gameplay, and the DOA Xtreme series, which is the closest thing to a true Dating Sim with mass-market appeal in the US.) If the game plays out like a Choose Your Own Adventure, that's a Visual Novel.
If it feels like you're playing an RPG, trying to keep track of everyone's feelings about you and giving out presents, that's a Dating Sim.
Some original-English dating sims include Sim Girls, In a typical dating sim, the player controls a male avatar surrounded by female characters.
The most common objective of dating sims is to date, usually choosing from among several characters, and to achieve a romantic relationship.
The term "dating sim" is also often used incorrectly in English as a generic term for romance-driven games (ren'ai games), a subject matter which is stereotypically associated with the visual novel genre.
There are dating sims for girls and dating sims for guys.
In these type of games, you will be looking for a perfect girl/boy and convincing them to go on a date with you.