Three small, innocent words, but often a source to frustration. If you look them up in a dictionary, you understand why. These three words have one translation in common: to think.
Since tenke is the word most similar to think, it is not a huge surprise that this is the most frequently used word by English speaking persons. The only problem is that in Norwegian we only use tenke to describe brain activity…. Jeg skal tenke på det./ I´ll think about it . In addition we use tenke in the meaning of have planned to do something. Jeg har tenkt å gjøre det i morgen. / I have planned to do it tomorrow.
Consequently, almost every time you want to use tenke , you are probably supposed to choose between synes or tror.
Synes is used when you have actually experienced what you are talking about. Jeg syns filmen er god./ I think the film is good. (I have seen the film and know it for sure.)
Tror is used when you really don’t know by experience. Jeg tror filmen er god./ I think the film is good.(maybe you have read a review or talked to someone who has already seen it.)
As a rule of thumb: Synes is used when you have an opinion based on first-hand experience. If you have to base your opinion on information not experienced by your self,tror is the word to choose.
If you don`t have any information at all? Well, then I normally prefer to say: Jeg vet ikke! (I don`t know!)