17 In the same way, every good tree produces good fruit, but a bad tree produces bad fruit. (Matthew 7:17 CSB)
We are not always good at discerning good acts made with right intentions from seemingly good acts made with bad intentions. The world has become a place where even things that look good and right on the surface have an underlying current of wrong intent. Much money has been made upon seemingly good acts that, in the end, turn out to be simple greed at work.
There are still a lot of snake oil salesmen out there.
While we cannot always discern others motives we can control our own. I have found that when I focus upon my fruit, even the bad fruit of others touches me less. This does not mean I allow myself to be gullible, but more that I am watchful and cautious while doing my best to bear good fruit.
Does this mean that I may get taken advantage of at times? Yes. However, I have never seen a situation where I payed back a advantageous act with kindness turn out poorly. God seems to always work between the lines in allowing good fruit to trump bad.