A difficult passage to mefor me to read.

I don't understand the part of "if there be diamonds there" inpart of what the mom's saying.

Is this an old expression?

Kinda. You typically see this speech with pirate like characters. In this case, it's just them not conjugating the word "to be" to "are"

Does this mean "if there will be diamonds there"??

I mean, it could. But it's more natural to see it as "if there are"

Is a version phrase withoutthis a phrase that omits the word "will"???"

In the story, a young man wanted to go abroad to look for diamonds to beand get rich , but his family opposed his idea.

Side note: technically, when you recount a novel/show/movie, you use present tense because the story happens again every time you read/watch it. It's not big deal though, especially in casual conversation.

Is there a version of the phrase without "will"??

ALSO POSSIBLE: I'm reading a novel and there'swith a passage difficult for me to understand.

In the story, a young man wanted to go abroad for diamonds to be rich in search of diamonds to obtain wealth, but his family opposed his idea.

OnlyPTION A: However, his mom supported hims plan. OPTION B: However, his mom was supportive of his plan.

The mom said to him, "You do what you must, son.

I don't understand the part of "if there be diamonds there" in the mom's saying.COMMENT: The mother is unsure whether diamonds exists where her son wants to go. However, she believes in her son's ability to find the diamonds *if* they actually exist in that place. Is that clear?

Is this an old expression?ANSWER: No. It is a hypothetical states. The core is: "If X exists, (I believe that) you will find it."

Does this mean "if there will bare diamonds there"??

GRAMMAR: In this case, "will" is the best word. There is uncertainty. Maybe diamonds exist there, maybe not.

Is a version phrase without "will"??[SEE ABOVE]

Could I say "I don't know if/whether there are diamonds there, but if there are, you'll find them" for that sentence?

Perhaps "whether" is a better choice than "if". (Whether is binary: either YES or NO.)

In the story, a young man wanted to go abroad to build wealth by searching for diamonds to be rich , but his family opposed his idea.

Is this an old expression?

Yes, it's an old fashioned, colloquial way of speaking. Pirates used to speak this way, e.g. "Yarr there do be treasure over thar"

Could I say "I don't know if there are diamonds there, but if there are, you'll find them" for that sentence?

Yes, this is much more natural / modern

In the story, a young man wanted to go abroad for diamonds to be rich , but his family opposed his idea.

This is actually fine, but it;s for natural to say "...to get rich." or "to become rich" :)

I don't understand the part of "if there be diamonds there" in the mom's saying.

So I think this actually sounds like she is a pirate or something :D I think maybe this is part of her regional dialect or she is maybe from Cornwall in UK.
In natural English we would normally say "if there are diamonds there". And I suspect that you already correctly thought that :)

Is this an old expression?

It sounds like its very old (but not grammatically correct) or a pirate :D

Does this mean "if there will be diamonds there"??

Yes, exactly.

Could I say "I don't know if there are diamonds there, but if there are, you'll find them" for that sentence?

This is exactly correct, yes. This is much more natural.

I'm reading a novel and there's a passage too difficult for me to understand.

Could you teachll me the meaning?

"Teach" is okay but "tell" is more natural.

I don't understand the part of "if there be diamonds there" in the mom's sayingpart.

Is this an old expression?

It's more like an dialect rather than an old expression.

Does this mean "if there will be diamonds there"??

It does!

Is this a version of the phrase without "will"??

Could I say "I don't know if there are diamonds there, but if there are, you'll find them" for that sentence?

you can.

It would be nice, if you could advise me.