swear by

listen to the pronunciation of swear by
İngilizce - Türkçe
İngilizce - İngilizce
To wholeheartedly trust

I swear by my Petit Larousse when it comes to learning French.

If you swear by something, you believe that it can be relied on to have a particular effect. Many people swear by vitamin C's ability to ward off colds
take an oath on -; give full trust to -
swear by