The correct spelling of the phrase "be worry" is actually "be wary" [bi ˈwɛri]. The word "wary" means to be cautious or on guard, and is pronounced with the "w" sound at the beginning followed by a long "a" sound (as in "hay"), then the "r" sound and a short "i" sound (as in "hit"). Thus, it is important to ensure that we use the correct spelling to convey the intended meaning and avoid misunderstanding.
The phrase be worry is not a conventional expression or a commonly used phrase in English. Therefore, it does not have a specific etymology. It appears to be a combination of the verb be and the noun worry used together in a grammatically incorrect manner. The word worry alone, however, derives from the Old English word wyrgan, which means to choke or to strangle. Over time, it evolved to take on the meaning of to be anxious or to be troubled.