how To Gain Trust

Trust may be the most important factor in successful relationships.[1] A person trusts another when they feel that they can be vulnerable and everything will be alright. You can build trust in your relationships if you are prepared to make the effort. Building trust requires making a commitment to trustworthy behavior.

Do what you say. One of the most important steps in building a foundation of trust is to do what you say you will do.[3] Even if it is a small thing, canceling or failing to follow through will create hairline fractures in your trustworthiness.
Although the occasional failure to follow through may not seem like a big deal; repeated failures can add up. Over time, people in your life may come to see you as less trustworthy.

Honor your promises. Trust requires that people believe you will be dependable in the long-term.[4] Thus, when you make someone a promise, you must keep it.
If you truly cannot keep a promise you've made, explain face-to-face why you cannot do as you said you would.
Especially if your promise was a major one, an explanation might not be enough. You may need to make a new promise to make it up to that person. Be sure to keep this new promise, no matter what!
Do not belittle the original promise. However small and insignificant a promise may seem, realize that the other person may place great significance on it. Any lack of follow through could be hugely disappointing.

Be consistent. An important part of the definition of reliability is following through with your word many times over an extended period. By definition, someone reliable is someone you can almost always count on.
Keep in mind that doing what you say only once or twice won’t build the solid foundation of trust in your relationships that you want.