"它真的值得一看"翻译成英语是？？

这两者都对,不过更正确的用法应该是It'S really worth a visit.
It'S really worth seeing听起来有点死记硬背,翻译英文的感觉.
所以最好使用It'S really worth a visit.

它真的值得一看
It's really worth seeing.

如果是表示某个地方值得一看,还是用worth visit 比较好.
worth seeing太中式英语了.

It is worth visiting/seeing.

it is worth to visit.
这

it is worth a visit
it is worth visiting