What happens during winston's next encounter with the young woman? How does he feel about it?

I'm not exactly sure where you mean but I’m thinking this is when Julia passes her note to Winston in front of the telescreen. Winston is terrified. He is almost sure this girl (Julia) is a spy for the thought police. The note he reads simply says "I love you" which confuses Winston even further. He is still terrified of her but is willing to take a chance on her just to feel something real.