The correct writing (as shown in the picture) and pronunciation of the six-character mantra:

The six-character phonetic notation Om (ōng) Well (mā) Ni (nī) Ba (bēi)? (mēi) Hum (hòng)

Om: read (ōng buzz). ōm is the correct pronunciation, OM=AUM, and you have to close your lips at the end.

What: ?ī is a retroflex sound. When pronouncing it, the tip of the tongue should be tilted up against the roof of the mouth, and then the ?ī sound should be released.

Ba: There is a consonant d after bēi, which is omitted in both Chinese and Tibetan. It can be read as bēidemēi, de means light and short, passing by. : mēi Other writing methods include [口+MI], [口+MI], etc. To be pronounced as mēi, not mī, it is derived from the locative case of the Sanskrit word.

Hum: Pronounced as (hōng 徽), there are also books with the pronunciation as (hòng). You can pronounce it in one tone or four tones. You can realize it by yourself according to the scene and your wishes. Most of the time, it is pronounced in four tones.

Extended information:

The six-character mantra, also known as the six-character Dharani, the six-character maxim, the six-character mantra, and the mani mantra, is the heart mantra of Guanshiyin Bodhisattva. In Sanskrit, this mantra contains the endless blessings and compassion of the Buddhas. It is the sound of the compassion and wisdom of the Buddhas. The six-character Great Ming Mantra is an expansion of the three characters "Om Ah Hum". Its connotation is extremely rich and mysteries are endless. It contains The great power, great wisdom, and great compassion in the universe. This mantra is the subtle original mind of Guanshiyin Bodhisattva. Regular recitation has incredible merits and benefits.

In fact, it is praising the vajra and lotus. It originated from ancient India and was called the praise of Shiva's forest cane.

Tibetan Buddhism regards these six characters as the source of the classics, and advocates that believers must recite them repeatedly in order to accumulate merit, complete their merits, and achieve liberation. Tibetan medical texts believe that the poetic interpretation of the six-character mantra is: "Wow! The treasure of Lotus Lake!" As mentioned above, the classics teach us to "take its sound, not its meaning." This is the correct way to learn the mantra of Dharani. Each word represents the subtle original mind of Avalokitesvara Bodhisattva, and the words cannot be interpreted with worldly wisdom. Recite the mantra with one mind, listen to the sound of the mantra, and focus on the sound of the mantra in your mind, until the mantra is me and I am the mantra. This is the true Dharani cultivation method.

Reference material: Baidu Encyclopedia-Six-character Mantra