Translation:I like that blouse because it is quite comfortable.
In portuguese there is no word for "it". Every word is either masculine or feminine, while in English, all inanimate objects (e.g. a shirt) are neuter and only people (and to an extent animals) take a gender. So of course the translation can't be one to one. In portuguese, you say "The shirt, I like her", but in English this is incorrect, you have to say "The shirt, I like it"
I read all the comments, and I still don't understand why ela is used to refer to the shirt. It's been very well established by now the Portuguese has no word for "it", and that it's simply omitted.
So why is the sentence not "eu gosto dessa blusa porque é bem confortável"?