Query to compare 2 table results and filter extra records found in a table
For my testing, I just created a couple of temporary tables (#CN for ORIN and #INV for OINV).  You should be able to replace them with your above queries without too much difficulty.

The following query should be a relatively efficient query to get the results you want:

with cn as
(
    select
        *,
        ROW_NUMBER() over (partition by JrnlMemo order by DocEntryCN desc) as rownum
    from
        #CN
),
inv as
(   
    select
        Comments,
        count(*) as rowstoget
    from
        #INV        
    group by 
        Comments
)
select
    cn.DocEntryCN,
    cn.Comments,
    cn.JrnlMemo,
    cn.DocTotal
from
    cn
    inner join inv on cn.JrnlMemo = inv.Comments
where
    cn.rownum &gt;= inv.rowstoget
order by
    DocEntryCN;


Sample data used:

create table #CN
(
    DocEntryCN int,
    Comments varchar(20),
    JrnlMemo varchar(20),
    DocTotal int
);

insert into #CN(DocEntryCN, Comments, JrnlMemo, DocTotal) values
(67,            'reverse',     'kaka-19',       500),
(69,            'reverse',     'kaka-19',       500),
(70,            'reverse',     'kaka-19',       500),
(71,            'reverse',     'kaka-19',       500),
(74,            'reverse',     'kaka-19',       500),
(75,            'reverse',     'Rob-23',        750),
(77,            'reverse',     'Rob-23',        750),
(78,            'reverse',     'Rob-23',        750),
(79,            'reverse',     'Rob-23',        750),
(84,            'reverse',     'Paul-17',       1250),
(86,            'reverse',     'Paul-17',       1250),
(87,            'reverse',     'Paul-17',       1250)

create table #INV
(
    DocEntryINV int,
    Comments varchar(20),
    DocTotal int
);

insert into #INV(DocEntryINV, Comments, DocTotal) values
(1,             'kaka-19',        500),
(3,             'kaka-19',        500),
(5,             'kaka-19',        500),
(6,             'kaka-19',        500),
(7,             'Rob-23',        750),
(9,             'Rob-23',         750),
(10,            'Alex-09',        1000),
(11,            'Olma-08',        1150),
(12,            'Paul-17',        1250 ),
(13,            'Paul-17',        1250),
(16,            'Paul-17',        1250),
(17,            'Rita-99',        1300),
(19,            'Rita-99',        1300);


I should point out that the results will be slightly different from what you indicated in your Desired Results section because you have a Rita there with a DocEntryCN of 90, but no Rita entries in ORIN.  Otherwise, the results are the same.