She tried to 'smooth things out' [=end an argument or disagreement] with her daughter-in-law, but the damage was done.
They 'smoothed the way' for a quick end to the dispute. [=they made it easier to achieve a quick end to the dispute]
Her time at college wasn't all 'smooth sailing'. [=she had some problems/difficulties during her time at college]
(..) ' bellissima! It's beautiful! Guido, look, it's-a like it was paved by angels. Boy, I tell you what. I bet even the roads on the moon ain't this smooth. Doc, look at this! Shoulda tossed him into the cactus a lot sooner, huh? Well, he ain't finished yet. Still got a long way to go. (..)2006 Cars
(..) Say thanks, and I'll be on my way. That's all you gotta say. Whee-hoo! I'm the first one on the new road! Oh! It rides purty smooth. - It looks awful! - Well, it matches the rest of the town. - Oh! Red. Who do you think you are? (..)2006 Cars