The agenda generally inspires the greatest trust is seeking mutual benefit -- genuinely wanting what's best for everyone involved. It's not just that you care about others; you also genuinely want them to win. Yes, you're seeing a win for yourself; that's natural, desirable, and to be expected. But you're also seeking a win for all others involved. You recognize that life is interdependent, so you seek out solutions that build trust and benefit all.
The opposite of a mutual benefit agenda is a self-serving agenda: "I want to win -- period." If that's your agenda, you might get results. But you need to ask yourself: Are these the best possible results I could be getting? And: Are these results sustainable over time? The answer to both of these questions is "no."
Instead of building bridges of credibility and trust, you're creating roadblocks of suspicion and distrust.