Have you ever heard the term “lip service”? It means an expression of support for something without any action to back it up. The origins go back to the 17th century, when kings and monarchs would give verbal support for military help to their neighboring countries, but wouldn’t back it up with actual soldiers.
Nothing will hurt your credibility and your reputation more than to give lip service to your friends and acquaintances. Once you prove insincere, they will never take you seriously again. If you tell someone you will call them, make sure you call them. If you sign up for something, show up to do it. If you express your love for someone, treat them with love.
Talk is cheap. Anyone can say stuff. Most people will take you at your word. Until your word is no good.