It means you can tell them anything and they wont say a thing about it but to you. It meams they will help you through any troubles ahead. They will do something for you if needed. A great example of this is gracen price. Because she has helped me through recent troubles and she keeps my secrets like her life needed it.
Oh my goodness somebody needs help. Thomas you are an amazing guy and such a great friend. They are jealous because you are showing how a boy needs to be treating his girl and now you're competition and they have to step up to treat her better. Do not listen to them. Keep being you