"Chair" is pronounced as [tʃɛər] in English. The "ch" at the beginning is pronounced as a soft "tʃ" sound, similar to the "ch" in "cheese." The following "a" is pronounced as the "ɛə" diphthong, which is a combination of the "ɛ" sound (as in "bed") and the "ə" sound (as in "a" or "uh"). Lastly, the "ir" is pronounced as the "r" sound (as in "red").
In summary, the correct pronunciation of "chair" in English is [tʃɛər].