cynical
Believing people mostly act for selfish reasons, not kindness.
Cynical means believing that people are mostly motivated by selfishness rather than genuine goodness. A cynical person doubts others' sincerity and assumes hidden, self-serving motives behind kind actions.
When your friend volunteers at the food bank, a cynical observer might say, “She's only doing it to look good on her college applications.” When a company donates to charity, a cynical response is, “They just want good publicity.” The cynical view assumes the worst about people's intentions.
Being cynical is different from being cautious or skeptical. A skeptic asks for evidence before believing something. A cynic assumes people are lying or scheming, even when there's no reason to think so. If someone tells a cynic, “I'm helping because I care,” the cynic's automatic response is disbelief.
Someone who's cynical about politics might say, “All politicians are corrupt,” refusing to believe any of them genuinely want to help. A student cynical about school might claim teachers only praise students to manipulate them.
Cynicism can feel smart or protective, like seeing through fake niceness. But constant cynicism makes it hard to trust anyone or feel hopeful about anything. When you assume everyone's motives are bad, you miss out on real kindness and genuine connection.