Simple
She was given a necklace. A simple, silver necklace with a snowflake on the end of it. It was gorgeous.
Later that day, after Risa had opened the gift and was studying with Satoshi in the library, she asked why he had given her the present. He replied that it was close to Christmas.
"I know," Risa said. "But why this?"
"... Because you like necklaces?" Wow. Satoshi Hiwatari confused. It was so... cute.
Risa sighed and rolled her eyes. "I know! But why does the necklace have a snowflake on it? I mean... all my other friends gave me things surrounded around Dark or artwork or wings..."
Satoshi kept his eyes on his paper and replied, "Because you like snow. You said that snow was rare and special." He stopped writing, put down his pencil, and looked her right in the eye. "You're snow. You're rare and special. It takes someone with an open mind and a keen eye to see your true beauty."
She beamed, stood leaning over the table, and kissed his cheek. Satoshi began to blush and Risa giggled. "Thank you."
Wordlessly, he took her hand in his, and the two of them studied for the rest of the afternoon.