Trust is one of the building blocks of a healthy relationship. If your girlfriend is hesitant to confide in you, accuses you of lying or suspects you of cheating, it's clear that she doesn't really trust you. Her lack of trust comes from one of two places -- her own issues or how you have been acting. Understanding why she doesn't trust you can heal your relationship and help the two of you to get back on track.

Taking Time

Unlike that initial spark of attraction, trust isn't an instant part of your relationship. Trust takes time to build and requires each of you to prove themselves to the other, according to the article "What's Your Relationship Reality?" on the Stayteen.org website. If your girlfriend doesn't truly trust you, it's possible that you haven't been together long enough for her to do so. In the beginning of a relationship, or if you're just casually dating, the two of you may not know each other well enough to feel real trust. This doesn't mean that she won't ever trust you, she just needs more time.

Your Honesty

If your girl doesn't trust you, ask yourself if you're the one at fault. Honesty is a key ingredient in a healthy relationship. When you're not completely honest with your romantic partner, you leave her little reason to trust in what you say or do. This doesn't mean that you cheat on her or tell her outrageously awful lies. For example, something that seems small such as telling her that you're going to the library with friends, when you really go to the local diner instead, may give her cause to doubt you. If you truly care about your relationship, your best bet is to be honest with her and tell the truth. This will show her that you're trustworthy.

The Past is Coming Back

It's possible that your girl's lack of trust has little to do with you specifically. If she's had problems in the past with a lover who has cheated or lied to her, she may have lost trust with everyone when it comes to romance. Instead of jumping in to trust you, she may take a step back and hold off. Her lack of trust may also come from her younger years. When young children grow up not trusting -- or not learning how to trust -- their adult caregivers, they may have similar issues in adult relationships, according to marriage and family therapist Karyl McBride in her article "Plant Both Feet In Relationships!" on the Psychology Today website.

Her Fear

When your girlfriend doesn't completely trust you she may have a fear that you'll let her down or that she can't rely on you. If this is the case, her reasoning may come either from her own issues or from your behaviors. For example, she's always been suspicious and doesn't trust anyone. Whether this comes from her past or her personality, her lack of trust has nothing to do with you and everything to do with her own issues. You can reassure her that she can trust you, but she might need more -- such as professional help -- to move past her problems. On the other hand, if your behaviors seem somewhat suspicious, she may worry that trusting you will make her seem stupid in the end.