光明 (guāngmíng) is a noun for 'light' (broad brightness or radiance) and also an adjective meaning 'bright, promising' or 'openhearted, honest'. It is more formal and figurative than 光 (guāng HSK4 'physical light') and 亮 (liàng HSK4 'everyday bright'), and as an adjective it's broader than 明亮 (míngliàng HSK6 'shining'). For a promising future, 光明 is a set phrase, while 有望 (yǒuwàng) is a verb meaning 'to be likely'.