真【zhēn】

真 in front of an adjective means "really". Unlike 很, it carries its full weight, and it is a reaction rather than a description.

真 against 很

很 is the neutral filler that holds the slot before an adjective. 真 says the speaker is struck by it.

Because 真 is an exclamation, it does not sit comfortably in a question. jīn tiān今天zhēn真Lěng冷má吗 is not what you ask; use 很冷吗.

真的 for "really" as in "genuinely"

In front of a verb, 真 needs 的: 真的.

真的吗 as a response

真 as an adjective

真 on its own means "true" or "genuine", the opposite of 假.