It's actually quite an interesting question, especially given the genres you're looking at. These are the bigs ones you have to worry about:
ESRB (North & Central America): The ESRB has a strange system that jumps straight from T for Teen (13) to M for Mature (17), so no matter what you do, unless you take out all the bad language and any and all suggestive content in the dating sim side of things, you're looking at a big ol' M on your game.
PEGI (Europe excluding the UK and Germany, though PEGI also covers India, Israel, Pakistan & Quebec): Similarly, you'll probably get a 16 from these guys whatever you do, because you're not getting a 12. 18 is generally reserved for stuff like excessive language, extreme violence and nudity. Having the option to disable these things does not affect their opinion.
VSC (UK): Video Games are no longer governed by the BBFC, who were nice enough to give Brütal Legend a 15 rating simply because you could disable the language and gore. Unfortunately, the VSC uses the same rating system as PEGI, so while they can have different opinions to PEGI, you're still gonna end up with the same rating.
USK (Germany): These guys are a bit peculiar, prioritising violence as the main point for rating games. However, that's not to say that you can get away with absolutely anything, just that they're more lenient when it comes to suggestive content and bad language. Good ol' Germany.
CB (Asutralia): List of banned video games in Australia. These guys have got to be the pickiest, most sensitive bunch who've ever rated anything ever. I'm not saying your game is going to be banned, I'm just saying that you're wayyy more likely to get a higher rating from this particular board. Honestly, the fact that it's part dating sim will make them think twice. And the worst part is, I'm not even exaggerating. I really wish I was.
Japan: Here's where things get really interesting. Note how I didn't put a specific board name for the Japanese. That's because they, naturally, have 3 different ratings boards, 2 of which are specifically tasked with rating PC Games of the Dating Sim, Visual Novel and Eroge genres. If your game is being released for PC, your game will be rated by the CSA and EOCS, simply because it has Dating Sim and Visual Novel content. However, if your game is for console or mobile, then it will be rated by the CERO instead, because they deal with any and all video games not on PC, as well as any PC Games not of the aforementioned genres.
What's also interesting is the criteria the CERO gives for it's B (12+) rating:
Contains some content parents may not like for children under the age of 12. May contain mild sexual content, some violence, mild horror content or infrequent use of profanity.
From what I can tell, mild sexual content and infrequent use of profanity fit your game pretty well. So where you'd likely get a 16 in Europe, a 17 in North America and an 18 in Australia, you'll probably get more like a 15 in the UK and Germany, and a 12 in Japan.
I swear, in terms of what they prioritise as acceptable in modern society, Japan and Australia are real polar opposites.