That's right. Even if you don't say "I promise", agreeing to do something is making a promise. You're giving your word and your word should be your bond.
This society doesn't give a damn about honor any more. They have no problem saying one thing then doing another.
This happened to me tonight. A close friend said he'd do things for me. Took my credit card and 6 hours later returned with ....NOTHING. Then got pissed at me for me having believed him and taking him at his word.
I'm sorry. I'm an honorable person. I try very hard to stand by my word and if for some reason I can't I inform and communicate with that person. This behavior is apparently frowned upon and I'm at a loss as to why.