Lovely
Dreamy, Beautiful
な adjective
The element of enemy isn't something you should think of as bad. You have to have the "enemy element" if you are to have lovely, dreamy, and beautiful things too. This is a good word when you're talking about some dude you think is hawt. Doesn't work as well with girls.
すてき
This is a jukugo word, which usually means on'yomi readings from the kanji. You haven't learned this reading for 素 yet, so here's a mnemonic to help you:
Oh wow, you look really lovely in that suit (す). Yes, I can see you through the Internet, and I have to say, that suit is just dreamy! Don't ever take it off.
彼の他の人を助けたいっていう熱意が、素敵だなって思うのよね。
I find him attractive because of his enthusiasm for helping others.