swear by

Idioms  

1. Have great reliance on or confidence in, as in She swears by her personal physician . [Early 1800s]

2. Also, swear to . Have reliable knowledge of, be sure of, as in I think she was going to the library but I can't swear to it . [Mid-1700s]

3. Take an oath by, as in I swear by all the saints in heaven . [Early 1200s]

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Example Sentences

Some people swear by this, but it takes a lot of tending.

From The Wall Street Journal

“At the end of the day, the government is going to go with systems that have been deployed, where combatant commanders swear by the fact that they want one of what we have,” Mengucci said.

From Barron's

It’s true, some of the world’s top CEOs and elite athletes swear by early rising.

From The Wall Street Journal

Lavender sleep masks, massages and mind tricks involving socks: Jet-setting bosses swear by these hacks that they say don’t require flying business class.

From The Wall Street Journal

People swear by it, but a lot of these things have a placebo effect.

From The Wall Street Journal