Are these sentences fine?

[Rihan]

You will be let to come here?( here the speaker wants his students to come and give their speeches)
I feel sometimes.( anything the speaker feels )

Thanks.

[5jj]

No.

I do not really know what you are trying to say in either sentence.

1. ? You must come here/? I want you to come here/?You are allowed to come here.
2. ?

[Rihan]

In the second sentence, I wanted to express that someone was not a good person or anything.
So , other someone asked someone 'don't you feel that you are really a bad person?' Then someone told other someone 'I feel sometimes.'

In the first sentence , The teacher wants his students to come here for giving their speeches.
You(students) will be let to come here

[emsr2d2]

In the second sentence, I wanted to express that someone was not a good person or anything something similar.
So, other someone asked someone else "Don't you feel that you are really a bad person?' Then someone told other someone can that person reply 'I feel sometimes'?

"I feel like that sometimes". If you say "I feel sometimes", it just means "Sometimes, I feel" which is not grammatically correct. You need to say what or how you feel.

In the first sentence, the teacher wants his students to come here for giving to give their speeches.
You(students) will be let to come here.
I'm afraid this still makes no sense. Your sentence does not mean at all what you want it to. What is your understanding of the verb "to let"?

See above.

[Raymott]

In the second sentence, I wanted to express that someone was not a good person or anything.
So , other someone asked someone 'don't you feel that you are really a bad person?' Then someone told other someone 'I feel sometimes.'
You can say, "I feel that sometimes". But such a sentence is hugely more understandable if it follows such a question as you've now given for context. You should give such context in your first post.

In the first sentence , The teacher wants his students to come here for giving their speeches.
You(students) will be let to come here. No.
"Come here and give your speeches." This is still a strange sentence, since it's unlikely that a teacher actually say it that way. But there's no "letting" involved. He is either inviting them, or commanding (ordering, requesting) them. It's true that he is letting them come and make their speeches. But if you tell someone to do something, it's implied that you have to be allowing (letting) them [to] do it.

ems has corrected your grammar, so I won't bother with that.