You had me worried for a moment with "I like to believe". I considered suggesting the litany of Tarsky, where you basically want to believe whatever is true, and not get too attached to beliefs you may not want. I now see it was just a figure of speech.

Now, would I trust people who would behave dishonourably around people they deem dishonourable? Well, probably less. I’d fear they might flag me as dishonourable, and one sidedly turn what could have been a tit-for-tat into an eye-for-an-eye. I’d be cautious for sure, but I’d most likely still give them the benefit of the doubt until they give me concrete cause to write them off.

Whether that’s a good strategy is another question, though. (For instance, Littlefinger did tell Ned Stark not to trust him, and Ned, being the bloody paragon that he is, trusted the sleazy bastard anyway, and lost is head for it.)

Be careful about getting life lessons from movie scripts :-/

But people do often unwittingly telegraph that they are untrustworthy. One of the obvious tells starts with "You can trust me!" In isolation, it doesn't mean the person is untrustworthy, but it is a warning beep.

I think there's more to it than just that:

Being around good people can inspire you to try to become better yourself.

Being around good people can give you the nudge you need to behave better when that's difficult.

Lastly, as much as I admire the ideally, I simply don't believe in turning the cheek at all times. It exposes other people to risk, not just yourself. (Perhaps that's not what you're arguing for though.)

(I think I understand the general point you're making, and agree with you partially.)

Turning the other cheek is something different altogether.