"tôi đối mặt thất bại" nghe vẫn hiểu mà
It's still right. But people usually use "đối mặt" with "với" more than omitting it.
Yes, but it is better to say ''tôi đối mặt với thất bại''.
The author seems obsessed with failure and success XD
They probably wanted to work in the abstract nouns from the last set of lessons.
It takes 'thất bại' too, it seems the sự is optional.
At least here, you never know what the next exercise zaps...