Trust can be on different levels my friend. If you are referring to trusting your spouse then TRUST THEM WITH ALL YOUR MIGHT. They wil in turn trust you gradually and it will last a lifetime. Or create a scene where you can make her/him believe that you deserve their trust.
I believe that once you know your partner and that you've recognized his loyalty and his honesty to your relationship, you CAN trust him. When you get second thoughts about the relationship, you just...
Tell her the truth! The best thing you can do is apologize and tell her the truth! If you've done some untrustworthy things before it's really up to her if she really wants to trust you again. Tell...
By always being truthful to her and not going behind her back with some other girl even if she does not know her. You should always tell your girl the truth even if she gets mad at you she will know...
First of all, make sure you don't say anything that you won't keep. If you do, and you don't keep your word to it, who knows what he might do. Promise him you'll never put him through what his ex put...
To gain trust, endeavor to always be truthful, do not promise what you cannot deliver, and do what you say you will. This is not everything, but it sure will go a long way!