The Congress had won the state elections in Rajasthan, and the people were extremely disappointed by Vasundhara Raje's governance. However, most political analysts say that BJP will win a majority in the Lok Sabha elections of 2019. How is this possible? What is the difference in people's mind that they choose the very party that they rejected and had so much anger against?
Different faces, different results
In elections regarding legislative assembly, people vote for chief minister while in election regarding Lok Sabha people will vote for prime minister(indirectly). It is not necessary that people only vote for a particular party, some chose to vote for individual people regardless of which party they represent.
Constituencies will be different in these two elections, which can make a lot of difference. Given link is not directly related as there is little to no gerrymandering in India but give information for the significance of constituencies. https://en.wikipedia.org/wiki/Gerrymandering
Periodic nature of Rajasthan state elections. In state elections, there is a periodic nature. In other words, if we know that BJP/Congress win this election than it is very easy to guess they will lose the next one. This pattern is not observed in Lok Sabha elections.
Opinion polls and other analysing may or may not be a good guess.