“One of the most beautiful qualities of true friendship is to understand and to be understood,” according to the Roman philosopher Lucius Annaeus Seneca. Good friends are generally in tune with what words will make each other smile. Sharing a spoken word with your best female friend doesn’t cost you anything, but could make her day when she needs an emotional boost.

Compliments and Appreciation

When criticism and complaints drag her down, make her smile with words of sincere and positive appreciation. A spoken, or written, word reminds your friend that she is valuable to you, according to Natasha Koifman, president of public relations agency NKPR, in “How Often Do You Appreciate Your Girlfriends?” for Huffington Post. Compliment her style, her looks, her intelligence, her abilities or the way she makes you feel. Express sincere and positive appreciation and watch her face light up. Don’t forget to say “Thank you” when she does something for you to encourage more smiles.

Humor Brightens Life

Humor can bring balance to your life, according to inspirational author William Arthur Ward. Share a joke, a personal humorous story or your favorite code phrase that always makes you laugh. As friends, you probably have many shared experiences that are funny and worth retelling. Start recounting a humorous incident and she will likely know exactly where you are going and begin smiling or laughing before you even finish the story.

Everyone Needs Encouragement

A good friend can provide encouragement and support when the path is bumpy, according to mind-body medicine physician Lissa Rankin in "The Health Benefits of True Friendship" for Psychology Today. Remind her that she has weathered other storms and she will get through this one too. Assure her that you are hanging with her so she isn’t alone. Tell her all the reasons why you know that she is strong, capable and successful. She might know all these things, but hearing them from you can help her tackle whatever is before her with a positive attitude. Add a hug or a pat on the back to add emphasis to your words.

Words of Love

Let your friend know that you love her. Jazz it up by saying it in different languages or dropping an air kiss her direction. Tell her that you can’t imagine your life without her or that no one brightens your day like she does. Tell her all the reasons you love her, such as the way she has your back or the way you can sit together in silence and feel supported. You can never say “I love you” too often if you say it sincerely.