I think she had trust in the healing power of Christ..she must have heard about Him and very quietly without calling attention to herself,came to touch his garment.Faith like this is just inherent in nature...like a child trusting its parents without anyone teaching or telling them...

this is the same faith that is called for us to have...child-like faith...never doubting always trusting.Jesus himself said about having faith as little as a mustard seed which is absolutely dense within-no room for anything else...that kind of complete faith is all we need to have in God