Let's say that I'm doing my daily labor, and it's a pretty hard work in general.
And someone offer to help me, without I that asked for it, and surprisingly that person invested in that job a lot more than I could imagine.
Could it be possible that my only option to gratitude him is to say something like:
Thank you for your effort?
What I really want to know, if there is any better way to rephrase the word "effort" to something more suitable that can describe how much I appreciate what he had done.