In English, when you are not 100% sure of something, use ‘I don’t think’ rather than ‘I think ~ isn’t’.
Wrong
I think it won’t rain.
I think he is not my type.
I think that when I get home my mother won’t be at home.
I think they can’t handle it.
Correct
I don’t think it will rain.
I don’t think he’s my type.
I don’t think that when I get home my mother will be at home.
I don’t think they can handle it.