I tried familysearch.org and thee were many William's listed
ancestry does not have it either.
You might have to get it from Vital Records Arkansas, it should not cost much
and I believe you can do it online.
There are a lot of cemeteries listed on Rootsweb, if you want to check each one. Takes time, but may save you a few bucks.
Good luck in your search

Marriages Records Arkansas
Name: William M Evans
Age: 21
Birth Year: abt 1870
Residence: Alston, Franklin, Arkansas
Spouse's Name: Margaret F Adams
Spouse's Age: 17
Spouse's Residence: Alston, Franklin, Arkansas
Marriage Date: 9 Sep 1891
Marriage License Date: 7 Sep 1891
Marriage County: Franklin
Event Type: Marriage
FHL Film Number: 1034245

Name: Della Evans
Age: 4
Birth Date: Oct 1896
Birthplace: Arkansas
Home in 1900: Wallace, Franklin, Arkansas
Relation to Head of House: Daughter
Father's Name: Willie Evans age 30 1870
Father's Birthplace: Arkansas
Mother's Name: Margaret Evans age 26 1874
Mother's Birthplace: Arkansas
Letha age 2/12
Source Citation: Year: 1900; Census Place: Wallace, Franklin, Arkansas; Roll: 58; Page: 9B; Enumeration District: 193; FHL microfilm: 1240058.

Name: Willie Evans
[William Evans]
Age: 30
Birth Date: Nov 1869
Birthplace: Arkansas
Home in 1900: Wallace, Franklin, Arkansas
Relation to Head of House: Head
Marital Status: Married
Spouse's Name: Margaret Evans abt 1874
Marriage Year: 1891
Years Married: 9
Father's Birthplace: Tennessee
Mother's Birthplace: Arkansas

Name: Sello Evans / [Della Evans]
Age in 1910: 13
Birth Year: 1897
Birthplace: Arkansas
Home in 1910: Brinton, Pottawatomie, Oklahoma
Relation to Head of House: Daughter
Father's Name: William M Evans 37
Father's Birthplace: Arkansas
Mother's Name: Margret Evans 37
Mother's Birthplace: Arkansas
Sello (della) 13
Jessie 7
Fay 5
Fate 1-9/12
Marion G. Adam(s) 45 brother in law 1865 MO
Source Citation: Year: 1910; Census Place: Brinton, Pottawatomie, Oklahoma; Roll: T624_1271; Page: 5B; Enumeration District: 0200; Image: 269; FHL microfilm: 1375284.

Name: Margaret Evans
Age: 46
Birth Year: abt 1874
Birthplace: Arkansas
Home in 1920: Wallace, Franklin, Arkansas
Relation to Head of House: Wife
Marital Status: Married
Spouse's Name: William Evans age 50 1870 AR
Father's Birthplace: Tennessee
Mother's Birthplace: Illinois
Able to read: Yes
Able to Write: Yes
children
Della 23
Jesse 17
Fay 14
Joe 11
Milburn 5
Samuel D Adams 52 Brother in law 1868 MO
Source Citation: Year: 1920; Census Place: Wallace, Franklin, Arkansas; Roll: T625_62; Page: 11B; Enumeration District: 49; Image: 826.

Name: Margaret Evans
Birth Year: abt 1876
Birthplace: Arkansas
Home in 1930: White Oak, Franklin, Arkansas
Marital Status: Widowed
Relation to Head of House: Head
Father's Birthplace: Illinois
Mother's Birthplace: Missouri
CHILDREN
jess 27
milburn 15
atha 20
Source Citation: Year: 1930; Census Place: White Oak, Franklin, Arkansas;
Roll: 74; Page: 6B; Enumeration District: 32; Image: 940.0; FHL microfilm: 2339809.