Non Muslim question about terms

Hi there, I'm a white, non-muslim woman, and have a lot of friends and colleagues who are Muslim. I honestly consider some of them more my family than my blood. After spending years with them, I've picked up the meaning and significance of certain words and terms. In the past I've had people ask me to say wallah to swear on things, even knowing I'm not Muslim or Arabic, I have, because that means a lot to them, and I know not to use it lightly or falsely.

I have however had some thoughts, I don't want to be rude or offensive to anyone but I still want to show the significance at times of what I'm saying/promising. Is it okay to say wallah?

Thanks for any advice! 👍🙏