"So I have this friend and when we first met she was really nice and we connected, we became best friends like right away. 3 months later she moved but not far just 10 minutes away (she used to live 1 block away) so at first we were still really close but then she started lying about everything. I found out she lied about stuff she told me when she first met. She said she had no friends then a couple weeks ago she started school and she was saying how much fun she has had with all her friends. This one time we had a sleepover and she left and ignored me for 2 weeks. Then she finally she called me and started lying again. Today my mom picked her up after school (I am home schooled) and she was going to spend the night and 1 hour after she got to my house she said “I started my period and need to go home” she hasn't started it yet but she thinks she is going to start it soon. But I can tell she was lying and so could my mom so my mom talked to her and she lied to my mom to then we took her home and she was happy and looked like nothing happened. I felt really sad and mad. I felt like she didn't care about me at all, and that feels really horrible. I care about her a lot and have forgiven her for everything. But if I confront her about lying she lies again. I don't know what to do now. I feel like our friendship was built on lies. She is the only friend I have right now and I am afraid of letting go. I am also afraid of hurting her. What should I do now?"
This sounds like a very difficult situation, and I’m so sorry you’re going through it. As someone without many close friends, I totally understand how important the friendship you do have could be to you, even more so than it would be otherwise. I admire how much you care for your friend—and forgiveness is an essential ability for life, so it’s great that you feel able to forgive her!
However, sometimes friends do change as you age (that much is only normal), and a healthy friendship or relationship of any kind needs to work in both directions. Of course you don’t want to hurt her, but the fact is, your feelings here matter too. In the end, it’s not going to be good for either of you to let things stay like this, if it doesn’t feel like she’s taking your own feelings into account.
There’s a lot to say in this scenario, and it’s hard to know what would be most helpful, but I’ll do my best.
If you’ve tried confronting your friend about the situation before and she hasn’t reacted well, that makes things harder, but another try may still be worth it. You could try starting out with something along the lines of “I have something I want to talk about, and I need you to listen to what I’m saying and respond honestly, because I’ve been feeling lately like you…” (fill the blank with whatever you want to say to her). I’d recommend trying to sound as nonhostile as you can, so she doesn’t feel like you’re trying to pick a fight. That said, your friend should know that this is important, and you need her to take it seriously. I completely understand not wanting to hurt her feelings… but it’s not hurtful to respectfully bring it up and explain your feelings. If she feels bad for it, in a way that’s a good thing. It means she cares about you, and feels remorse for what she said or did. That’s how it should be, and even if it’s not fun in the moment, it’ll be worthwhile eventually.
If you preface what you bring up by making it clear what’s happened when you’ve tried talking to her before, it’s always possible she’ll rethink things and make more of an effort towards honesty. Maybe she hasn’t even realized that she hasn’t been being honest. (It sounds ridiculous, but it’s true: Sometimes people genuinely aren’t aware of these things in themselves, even if it may seem obvious to everyone else.) Or who knows—maybe some of the things that come across as dishonest are actually truer than you might realize (for instance, maybe it's true than when you first met her, she didn't have other friends, but she could have made some since then). Talking about it again gives both of you a chance to communicate openly and respectfully with each other.
If a non-accusational discussion still doesn’t work, or you find her lying again and again in hurtful ways, it might be time to question whether the friendship is really still an overall positive experience for you. Do the favorable, fun times outweigh the unpleasant times or the lies? When you’re with her, do you feel happy more often than you feel upset? Are you getting more good out of your friendship than bad? If the answer to these questions is no, then how much do you want to hold on to this? A good friendship is mutual, with both sides considering the other’s feelings—not just one.
If it does seem that you’re losing more than you’re winning here in terms of friendship (and I can’t tell you whether you are; that’s something best to figure out for yourself, I’m afraid), you definitely don’t have to completely cut off your friendship if you’d rather not. Gradually distancing yourself instead can be another, less jarring, option, and hopefully less upsetting for you both, if you do decide that that’s the best option here. Remember to try to understand what she's going through, but if the friendship doesn't feel built on anything real, there's not much good in it for either of you to maintain things as they are.
One final suggestion before I go: It seems like your mom knows about what’s going on, at least to some extent, would that be correct? It can sometimes be easier for people who witness and understand what’s going on directly to give useful advice than someone like me, who only knows about it secondhand, and only the limited information that you included in your letter. I’m guessing she knows more details than I, and you might want to ask her advice as well. She could well have some helpful suggestions.
I realize I wrote a lot here (and with lots of "if"s!), and I hope you were able to follow it all; I apologize if it’s not all helpful advice, and wish you the best of luck—I hope everything ends up well! And remember, no matter what happens with this, no matter how few or how many friends you have IRL, I’m here, as is the rest of NMG. It’s not quite the same as face-to-face friends, I know, but we’re here for you, and you can always send me a private message if ever you need. <3
Hope this helps! :)