Istikara

Doesn't always work, possibly because that is not the question you are supposed to look at. It is sad that parents just pair people up -you a male this one is a female and just get married and you hear horror stories.

Here, you are asking Allah to do the basic work for you-which is not done, he has given you senses, so people like your parents, should be finding out more information. There is nothing wrong with a father for example spending time, a few days with their son in law. Too much people are just going by word of mouth. Then they find out that it was all lies.

Here, there is a difference between asking questions (answers that you should have sufficiently asked and have answered satisfactorily), to asking questions then to Allah, when you have exhausted it and it is about the next best steps (and I don't think that a lot of it falls under that line and the jinn can mess about).

It is wrong to just ask Allah to do all the footwork in finding out the information-this is taking away communicating with others, building relationships -this prayer, which I believe you don't do more than 3 days at anyone time, is not to always be done. As marriage as per the Quran is between believing men and believing women - you should therefore not be having doubts regarding another muslim and then asking Allah to check if you should get married to a muslim - the companions in the past married readily to how many people. You just need to do the homework and check that the information presented to you are not lies. and if you like someone that should be enough.

It is disrespecting Allah to just say here is a muslim woman and I do not know if I want to get married to her, incase it doesn't work out-when marriage takes work. Based on both of your actions, you can say if you don't like someone in how they look, and be careful if you think there are behaviours like being addicted to social media which would cause problems.