Townie Dates
How about to have Townie Sims in a Relationship randomly?
SimBlender does not work properly I tried.
Need Better Mod for NPC non playable characters and Townies in a relationship.

ACR will make sims hook up randomly. Not sure what you are trying to do with the sim blender exactly?

ACR is a huge, complex mod that I don't recommend installing until you've mastered the game enough to tweak it to your satisfaction. It is possible to make townies playable by choosing the propose - move in option, or by marrying them into the household (Propose - Engagement; then Propose - Marriage; or, buy a wedding arch, throw a wedding party, invite all your friends, use the arch to get married). It is possible to use the testingcheats (boolprop testingcheatsenabled true) to make a sim selectable temporarily; or to use an editing tool called SimPE to change a townie into a playable sim in its own household, but these might be a little advanced, since you seem to be still experimenting with game features. Generally it's a good idea to learn how vanilla game features function before using cheats and hacks to tweak them on any large scale.

I have found that townies and NPCs will make friends in the background of community lot visits all on their own, but you will need a mod if you want them falling in love on their own. Also, by default townies will lose their memories on being moved in, and their moods are locked in the Green range, so if you want them being ecstatic or going into aspiration failure in the background, or to be in high aspiration from dating and getting married when you marry them in, that's another mod.

ACR is pretty easy to understand. It has a certain amount of complexity, but you don't actually have to use all of the features, it works perfectly fine out of the box. This person obviously doesn't want to play with townies who were moved in as playables, they seem to want to make TS2 more like TS3, and adding mods that make more things autonomous will get closer to that. Moving in a bunch of townies will not.

There again you may be confused by The Sims 3 and 4. In The Sims 2 NPCs are divided to townies, downtownies, tourists, strays, service sims and game objects. All of them except game objects and some service sims you can make playable by moving or marrying in.
ACR has option to autonomous choosing a gender preference. Without ACR you can make a NPC chose a gender preference if you ask him/her with playable "Do you like what you see?"
NPC with gender preference will do all romantic actions with other NPC with gender preference by their own except Woohoo. NPCs cannot marry with each other or get pregnant.

ETA: You may be looking for age progression mod what is mod in beta testing.

You don't need no mods to have townies spontaneously fall in love, it happens all the time. I don't have ACR or anything like that.

Obviously it's not likely to happen unless you actually play with townies around. I spend a lot of time on community lots, and tend to greet most of the townies passing by my residential lots. If you often play dorms or apartment lots with townie neighbours it will also happen more often.

Another thing to try, if you are not seeing townies falling in love and starting relationships on their own, is to set their gender preference. Perhaps that's what you were trying to do with the Sim Blender? In any case, sims without a gender preference tend not to do autonomous romantic actions, so setting townies' gender preference through a mod (Sim Blender and ACR can both do this) can help. Like Annaminna said, if sims have gender preferences set, they can fall in love and start relationships all on their own--but note that it's still random, and not 100% guaranteed.

And as Lili975 pointed out, you're more likely to see this behavior if you have townies around often. Spend a lot of time on community lots, and in dorms, hotels, and apartments, and you'll see townies start to form relationships on their own. They won't do it off screen unless you have mods (the new Story Progression). And again, it takes time. If you want more instant results, I will suggest ACR as well; I agree with Kestrellyn--ACR isn't that hard to understand. I do recommend reading the instructions and the faq first, but first time users can easily just install and observe, then tweak the mod to their liking later. It's pretty much what you end up doing anyway.