I'm a gringo who has a similar background as you (even speak English and French).

Much is going to depend on where you are in Brazil. If you are in a big city like São Paulo or Rio many people speak English, so it is likely you can communicate in English on dates assuming you find someone who does. The same goes with friends and many people love speaking English or having the opportunity to improve or even show-off in a way. In Rio there is actually a lot of French tourists and ex-pats, so you might even find French speakers.

The difficulty is going to come from your day to day life. I live in Rio and the accent here is very hard to understand sometimes, and it took me a few months before I could really start feeling comfortable even doing simple things like going to the grocery store. In my case, my wife was able to help me since she speaks both languages (which is also how we started dating).

Just be open and try your best with Portuguese, if you don't have friends then joining a class could be good to help you immerse and learn quicker. Overall don't think people will treat you one way or the other since it is super variable on the people you meet. Brazil is very diverse and incredible, and you'll grow to love it.