Why is Lucy pevensie valiant?

She never deviates from the truth, no matter what it costs her to tell it.

She never loses her compassion for other people, no matter how badly they have treated her or how little she knows them.

She does not pity herself.

She is generous. She does not stop to worry about having nothing left for herself - she gives wherever there is a need.

She does whatever she has to do, without fearing for her own life.

When she is wrong, she faces up to it.

She trusts completely in Aslan.