Status is an official thing between the Sims, and once in a real relationship any flirting with other Sims will result in anger out of the boyfriend/wife/whatever.
Other socials are available depending on where the two Sims are. Therefore, build some Friendship before turning a conversation flirty and using Romantic socials.
If you have access to a couch, Sims can 'Make a Move' and put their arm around the other. You are truly more in control when wooing another Sim when at home, so do try to pick that as a great spot for a date. Sims with Level 9-10 Charisma get 12 toward success, and even 3-4 levels gives 3. You can see the other Sim's mood by hovering over the conversation box at the top of the screen, or simply by looking at the color of the bottom line.
Know that Romance is not restricted to Adults in The Sims 4.
This is also all relevant to Teenagers, who may exchange promise rings to indicate they will marry at some point in their adult lives, and even "mess around" as opposed to Woohoo. The Romance Meter When talking to a Sim, the top bar is for Friendship and the bottom Romance.
The context of the conversation notifies us of the buildup.
A Pleasant Conversation does not mean you can expect a Sim to allow you to suddenly kiss them.
Finding Love If you want your Sim to get along with their future husband or wife, then find a Sim that has Traits that you like.
You may also consider their appearance, as the game has a genetics system to determine that babies will look like their parents.
The Sims 4's Romance system is one of the things the developers did very well with the game.