Demonstrating our selflessness shows true intentions. It’s impossible to have a belief that wouldn’t reflect in our actions. Truthfully our actions are proof what we really believe. If a life of meaningful impact is what you truly seek, then selflessness is a cardinal virtue you have to demonstrate constantly continuously.
You should learn to be accomodating, open & helpful to people even when you barely know them. When this becomes your life habit, it is proof that you have attained some form of growth because truly mature people lead selfless lives. They are always ready to give and help the improvement of others. Two key lessons towards a meaningful living: SELFLESSNESS & BEING SELF-INVESTED.