It's fine to say, I will never intend to harm the dog in front of me, and I will always intend to improve their lives. As a professional, that's literally the least you can do. Meaning well is not the extent of your obligations: doing well is. Getting caught up in what you intend to do, or how you want the dog to feel, can lull you into a kind of moral myopia where you're so focused on your own good intentions that you're no longer able to assess harm from the dog's point of view first.
Telling people you'll never intend to harm a dog feels good. It's a promise you can make for free; you can splash it all over the Internet, sign petitions, tell your friends, whatever. But it's too easy to conflate feeling good about something with actually doing the right thing.
Whether you did the right thing is determined by more than your intention and how it makes you feel: it's whether you did everything you could to be in a position to help the dog in front of you in a way that minimizes their frustration and discomfort, not yours. If you intend to do some great training and the dog is indicating that they're having a miserable time, your intention doesn't make the training better.
Intention is only morally relevant when it's combined with controlling as many factors as possible to bring what you intend into reality. Otherwise, it's just a way to excuse incompetence, and it doesn't help anyone.
Instead of promising never to do harm (which is such a vague promise as to be meaningless in practice), promise to always work to improve your knowledge and skills, so you can choose the least invasive and least aversive interventions possible and use them effectively.
Promise to always look at the situation from the perspective of the dog in front of you, and always to ask whether you could be doing something better for them. Those are the kinds of intentions that make a difference to dogs.