conversely; on the contrary
逆に marks a reversal or contrast, meaning 'conversely' or 'on the contrary'.
逆に is used to present the opposite side of a statement or situation. It often appears when the speaker wants to say that the opposite of what was just mentioned is true, or to introduce a contrasting viewpoint. Unlike しかし (but), which simply connects contrasting facts, 逆に emphasizes a reversal of expectations or logic.
In conversation, 逆に can also express that something is the opposite of what one might assume. For example, if someone expects a task to be easy but it's hard, you could say 逆に難しかった. It's a natural way to flip the perspective. It is common in both spoken and written Japanese, but in formal writing, it might be replaced with 反対に, though 逆に is still acceptable in most contexts.