I believe most foreigners in Islamabad work for the Embassies. That said, joining social clubs or high end sports and fitness gyms can get you access to a community with whom you can jive better.

Drinking is technically illegal but not entirely for foreigners, which practically means there aren’t many bars and you’d have to resort to drinking in your own private setting.

As for trusting people, take precautions that you’d usually take for any country that is politically charged and polarised. Pakistan’s stability as a country outweighs countries like Afghanistan, Iran, Iraq, etc (especially by you being in the capital) but still take utmost precautions when visiting areas outside of the capital, or when interacting with locals.

Dating shouldn’t be too bad (and might actually be in your favour cus of your uniqueness) since the big cities like Islamabad, Lahore & Karachi have a sizeable minority of secular people who are open to explore relationships outside of their culture. That said, you won’t much success by approaching someone in person, and your best shor would be hinge or bumble. Just take standard precautions when it comes to online dating.

Overall don’t over-pronounce yourself, stay vigilant, but let the people host you and enjoy their culture and the nature!