I want to be there to hold your hand and shield you from any troubles that come your way.

Somes lines sound better than others. Some sweet things to say have to be used on special occassions. With this one, you cannot come out of the blue, but you have to wait for special occassion. And I cannot tell you when you should say: I want to be there to hold your hand and shield you from any troubles that come your way, however you will definitely be her hero of the day if you say it when she needs to hear that.