I also tried to find ways to get rid of my mistrust, but there seems to be no way.
As I mentioned above, I tried to write some meaningful posts, and then found someone who set me mistrust, he may help me to lift?
Showing distrust now has a big impact on me. If it can, I will try to delete it.
I have a hard time understanding what you're saying, but if i get your question correct, it seems like you're asking whether or not somebody will remove the negative trust on your account if you write some meaningfull posts?
Well, in the OP's case, The Pharmacist left him negative trust because he was suspecting this account to be farmed with low quality posts. In this case, if the OP proves he's a helpfull member of the community by cleaning up his act, The Pharmacist *might* reconsider (no guarantee).
In your case, it seems you were tagged by DannyHamilton and nullius because you were begging for merrit, even sending nullius unsollicited PM's begging for merit. In my honest opinion, just writing "some meaningfull posts" won't solve this problem. Just my personal opinion tough... I wasn't the one giving you -ve, so there's no way to be sure about this.
A real life example to try to explain it a bit simpler.
There are 2 guys on this forum i don't trust:
- one because he started a public crusade against me because i was helping people and asked some information in order to help them out, this dude claimed i was the worst person on bitcointalk and claimed his financial loss caused by my action of helping others was 1 million bitcoin. He made a whole thread where he dragged my name trough the dirt and stuff.
- the second dude was trying to get a service off the ground. I personally believed he wasn't a bad dude, but the service he was trying to start required a lot of BTC from the community and had a very, very, very big chance of going bancrupt, making a lot of community members lose a lot of BTC. I had a big altrecation with him
If both those people ran a business from the start, and made it a big succes, i'd start trusting the second dude again... However, the first dude would still be on my ignore list.
If both of them would write beautiful posts helping hundreds of people, they'd stay on my ignore list.
Bottom line: you can get neg tagged for numerous reasons, if you want to get untagged, you should fix those reasons. There is no generic sollution tough, what will fix the OP's problem won't necessarily fix yours. You should just accept that some of the reasons for getting -ve are "unfixable". 
