If you are described as winsome, take it as a compliment. It means you are attractive or charming in an open and delightful way. It doesn't mean you win some and you lose some.
The word winsome comes from the Old English wynn which means pleasure and delight. The word sometimes carries with it a feeling of childlike joy or innocence that is attractive or pleasing to others. There is nothing hiding behind a winsome smile. It wins over others in a fresh and honest way.