This is what you really need help with @Biba_yu. You KNOW this is asking too much of you, and you have shared plenty of good reasons why it's too much to ask of you which so many have validated here in your thread.

You have been conditioned to experience discomfort when you don't please and do things the way others expect of you (your mother instilled this in you because she is toxic). So, in essense when you put effort into doing something and make gains, you tend to experience what is called "cognitive dissonance".

Cognitive dissonance is when someone puts in effort and has boundaries but when they do put in effort to do for self, and have boundaries, they experience two or perhaps even three emotional challenges in their mind. There are angry feelings and kind/positive feelings this wanting to be good, but fearing something bad and it's like carrying this other negative in your mind constantly, as if haunting you. Some people describe this presence or challenge as being the inner child or a feeling of being small and helpless and fearful of something negative happening. This is the struggle you are describing experiencing that can last for days in you, this is what makes you "tired".

I believe you, I believe you want to be a "good person" and be a "good mommy" and you work hard to make a home for your child. I also believe you are likeable, that you work hard and do your best to be competent in your job too. I believe you appear competent and likeable, but you don't always FEEL that way, and thats because you carry this child in you that struggled to feel right because of a presence that never RESPECTED or allowed you to FEEL good when you did something or achieved something. Actually, Rose took time to learn more about you and noticed how you struggled with a mother that was not happy unless things are done HER way and she never really allowed you to feel "good enough". Yes, that does play a role in your ongoing challenge.

This is good, the way you articulated this. This is what contributes to YOUR cognitive dissonance, and how you struggle for so many days when you set a boundary, or put in effort. When it comes to a person like your mother, there is NO WIN. How awful for a child to have to grow up with that kind of presence. A child that FEELS IT but doesn't have a clue about what to do about it and learns that no matter what is tried, it's the same.

This is especially important to point out. This is what you saw happen many times, and YOU suffered the consequences from her decisions too. It actually affected you so much that you feel very uncomfortable attaining anything that holds you hostage in a way until paying it off. This is why you choose to save up to purchase instead. (smarter)

Yes, I bet your sister is nice, however, she is being like your mother in wanting a new car even though she and her husband are unemployed. And she wants satisfaction so much that she is asking you to be responsible for the financing. That is NOT anything you should ever agree to do. And that triggers that challenged inner child part who learned to feel bad when her mother did not get what SHE wanted. And because you have a job and are doing a good job at supporting yourself and your child, you feel guilty when you don't risk that to please your sister's needs? Like you somehow owe it to her to give in? That's not healthy thinking now is it? Would you want to teach your own daughter to feel that way? Or struggle like that? Ofcourse not because you want her to feel and be confident and see how her mother works hard and can support herself "responsibly". Also, if your daughter came to you with this challenge, I am certain you would advise her not to put herself at risk so someone else can have a new car, and someone else doesn't even have a job.

It sounds like your sister can be like your mother, not really thinking about the long term consequences when she wants something right now. What's even worse is how she even thinks it's ok to ask you to bear that burden where if she can't make it, you get left with the long term burden. And you worry about things going bad if you say no? Well, things can go VERY BAD if you were to say YES. And this has left you with that old struggle, that cognitive dissonance of "I can't WIN" right? When you work and get paid, you deserve to feel good about it, after all you worked for that paycheck. But you struggle to feel good, yet, that's this old crappy cognitive dissonance you were imprinted with as a child that you keep fighting. So what you need to do is work hard in your own mind to keep telling yourself YOU DESERVE to feel good when you work at being a RESPONSIBLE ADULT. Isn't that what you want your daughter to feel? Isn't that the example you are setting for HER? So, you have to not only show your daughter PRIDE in SELF, but also that inner child inside of you too.

You are not responsible for your sister or giving of yourself like this so she can get instant gratification. You are RESPONSIBLE for your own happiness and that of your daughter and you deserve to set boundaries for that and feel ok with it instead of the guilt you struggle with that goes very far back in you that your mother instilled in you.

What you CAN do is you can sit your sister down and let her know you love her, but you don't want to make decisions like you saw your mother make, and you work hard at being different and being responsible and you want your own daughter to experience something different than you did with your mothers need for instant gratification that led to bad consequences.

You don't have to present stories that can get her looking for a different way to ask you either. The best way to handle it is SPEAKING THE TRUTH.