They will trust you until you start keeping secrets from them. They need open communication in order to feel comfortable with another person. This means they want to know what you’re thinking, even if it’s uncomfortable or hard to hear. It doesn’t mater whether you think you’re saving them trouble by not bothering them with your petty problems, or whether you think you’re protecting them by keeping them in the dark. Either way, your secrets will push them away from you. They will never trust you again if they catch you omitting important information or actively pretending nothing is wrong when it is.
They will trust you until they catch you in even the smallest lie. To them, your word is everything. They need to know that you mean what you say, that there is no trickery or manipulation involved in the relationship. They can handle even the harshest truths, so there’s no reason for you to be deceptive. If they discover that you’ve been telling even the smallest lies, their trust in you is going to crumble. They’re going to start wondering whether anything you say is real. They won’t last in a relationship where they need to second-guess whether what you’re saying is the whole truth or only partially accurate. They need a partner that is transparent and honest, no matter the situation.
They will trust you until you make them jealous. They don’t want to feel like they’re in a competition for your love. They want to know that they’re the only person you’re interested in dating, that you have zero regrets about committing to them, that you still feel the same way about them now that you did when you started dating. If you are purposely making them feel insecure about themselves, they are going to distance themselves from you. They know their worth, and they know they deserve a relationship where there isn’t any question about how their partner feels. So if it seems like you might want someone else instead, you can have them.
They will trust you until you break a promise. It’s important that your actions match your words, that you actually follow through with the promises that you make. They don’t want you to say what you think they want to hear in the moment in order to shut them up or avoid a fight, unless you actually mean it. If you apologize and claim you’ll do better next time, but you never actually make a change, they can’t trust you. If you promise to take them on a vacation or to a movie soon and it never happens, they can’t trust you. There’s no reason for you to lie to impress them or make them happy because broken promises will only look worse for you in the end.
They will trust you until you stop trusting them. After all, trust is a two-way street. There should be loyalty on both sides of the relationship and trust on both sides. If you start accusing them of being unfaithful or mistreating you when they have done nothing of the sort, they are going to wonder whether you’re doing the same exact things you’re accusing them of doing. Even if you aren’t, it doesn’t matter because they need space and freedom in a relationship. They need you to trust them so they can go out and have fun on their own without it turning into a problem. If you can’t trust them, they can’t trust you either.