如 pairs woman 女 with mouth 口; early glosses read it as 'to follow what is said', which drifted into 'to be like, to accord with' — and from resemblance came supposition: if things were like that...
如果 'if' opens every hypothetical in Mandarin. 比如 for example, 不如 not as good as, 如意 as-you-wish (the name of the curved ceremonial scepter). New Year wish: 万事如意 — may ten thousand things go as you wish.
As the mouth 口 says, so it goes — LIKE, AS, IF.
百闻不如一见 'hearing a hundred times isn't LIKE seeing once' — the Chinese original of 'seeing is believing', with 如 doing the comparing.