If your friend is not seeing or involving with someone... Go ahead and tell her, why not?
The worst things that can happen is that she will say , she loves you as a friend... SEE ? not too bad right?
Love is a beautiful thing whether it happens among friends or lovers, never underestimate the power of love!!!
Being deeply loved by someone gives you strength, while loving someone deeply gives you courage!
so.. LIVE every moment, LOVE everyday... because before you know it, precious times slips away!