Exhibit 31.2



CERTIFICATION OF CHIEF FINANCIAL OFFICER

PURSUANT TO RULE 13a-14 UNDER THE SECURITIES
EXCHANGE ACT OF 1934

AS ADOPTED PURSUANT TO SECTION 302 OF THE
SARBANES-OXLEY ACT OF 2002



I, Sally F. Dornaus, certify that:



| | 1. | I have reviewed this Annual Report on Form 10-K of Bain Capital Specialty Finance, Inc.;
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| | 2. | Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to
state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not
misleading with respect to the period covered by this report;
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| | 3. | Based on my knowledge, the consolidated financial statements, and other financial information included
in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant
as of, and for, the periods presented in this report;
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| | 4. | The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining
disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the registrant and have:
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| | (a) | Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to
be designed under our supervision, to ensure that material information relating to the registrant, is made known to us by others within
those entities, particularly during the period in which this report is being prepared;
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| | (b) | Designed such internal control over financial reporting, or caused, such internal control over financial
reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the
preparation of financial statements for external purposes in accordance with generally accepted accounting principles;
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| | (c) | Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented
in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered
by this report based on such evaluation; and
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| | (d) | Disclosed in this report any change in the registrant’s internal control over financial reporting
that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an
annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over
financial reporting; and
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| | 5. | The registrant’s other certifying officer(s) and I have disclosed, based on our most recent evaluation
of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board
of directors (or persons performing the equivalent functions):
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| | (a) | All significant deficiencies and material weaknesses in the design or operation of internal control over
financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report
financial information; and
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| | (b) | Any fraud, whether or not material, that involves management or other employees who have a significant
role in the registrant’s internal control over financial reporting.
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Date: February 23, 2022



| | /s/ Sally F. Dornaus                
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| | Sally F. Dornaus                    
| | Chief Financial Officer             
| | Bain Capital Specialty Finance, Inc.