Thank you for the beautiful scarf. I’ll cherish it.
Princess Kristen's red hair is so beautiful it makes me cry.
Oh my, your eyes are as beautiful as jewels, Christine.
This is a single kanji with an い on the end, meaning you know it's probably an adjective. What's the adjective form of beauty? It's beautiful.
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you. It's a long reading for a mnemonic, but try your best.
You look at someone who is beautiful. What an easy life they've lived. No hard work and all they do is pamper themselves to stay beautiful. Feel disgusted. You walk up to this person and say: "U too cushy! (うつくしい).
Sorry for adding the whole word in there for the reading mnemonic, but I thought it worked out better that way. Just know that the word isn't うつくしいしい or something weird like that. The hiragana on the end is part of the mnemonic as well.