Rif Yevamot 44b {Yevamot 118b - 119a}

44b

{Yevamot 118b}
Mishna:

האשה שהלכה היא ובעלה ובנו למדינת הים ובאה ואמרה מת בעלי ואחר כך מת בני נאמנת
מת בני ואחר כך מת בעלי אין נאמנת וחוששין לדבריה וחולצת ולא מתיבמת

ניתן לי בן במדינת הים אמרה מת בני ואחר כך מת בעלי נאמנת
מת בעלי ואח"כ מת בני אין נאמנת וחוששין לדבריה וחולצת ולא מתיבמת

ניתן לי יבם במדינת הים ואמרה מת בעלי ואחר כך מת יבמי יבמי ואח"כ מת בעלי נאמנת

הלכה היא ובעלה ויבמה למדינת הים ואמרה מת בעלי ואחר כך מת יבמי יבמי ואח"כ בעלי אין נאמנת
שאין האשה נאמנת לומר מת יבמי שתנשא ולא מתה אחותי שתכנס לביתה ואין האיש נאמן לומר מת אחי שייבם את אשתו ולא מתה אשתו שישא את אחותה

A woman who went with her husband and his {and her} son to an overseas country, and she comes {back} and says "my husband died and afterwards my son died," {such that she is exempt from yibbum and chalitza} she is believed.
"My son died and afterwards my husband died," she is not believed {to permit yibbum}, but we worry for her words, such that she performs chalitza and not yibbum.

"A son was given to me in an overseas country" and she {also} says "my son died and afterwards my husband died," {such that she is eligible for yibbum} she is believed.
"My husband died and afterwards my son died" {such that the is exempt from yibbum and chalitza} she is not believed, but we worry for her words, such that she performs chalitza but not yibbum.

"A brother-in-law was given to me in an overseas country" {by her mother-in-law giving birth} and she {also} says "my husband died and afterwards my brother-in-law died," or "my brother-in-law {died} and afterwards my husband died," she is believed.

If she, her husband, and her brother-in-law traveled to an overseas country and she says "my husband died and afterwards by brother-in-law died," or "my brother-in-law {died} and afterwards my husband," she is not believed.
For a woman is not believed to say "my brother-in-law died" so that she may marry, nor "my sister died" so that she could enter her house {by marrying the widower}, and a man is not believed to say "my brother died" such that he will perform yibbum on his wife, nor that his wife is died such that he may marry her sister.

Gemara:

בעא מיניה רבא מרב נחמן המזכה גט לאשתו במקום יבם מהו כיון דסניא ליה זכות הוא לה וזכין לאדם שלא בפניו או דילמא כיון דזמנין דרחמא ליה ליבמה חוב הוא לה ואין חבין לאדם שלא בפניו
אמר ליה תניתוה וחוששין לדבריה וחולצת ולא מתיבמת
אמר ליה רבינא לרבא המזכה גט לאשתו במקום קטטה מאי כיון דאית לה קטטה בהדיה זכות הוא לה או דילמא ניחא דגופא עדיף לה
ת"ש דאמר ר"ש ב"ל טב למיתב טן דו מלמיתב ארמלו

Rava asked of Rav Nachman: If one gave over a get {to an agent on behalf of his wife, but he appointed this agent rather than she} in case of a levir {such that it is to her benefit, so that she need not undergo yibbum or chalitza}, what {is the law}?
Since she hates him {the levir}, it is a benefit to her, and we accrue benefit on behalf of a person even when not before them? Or perhaps since there are times that she loves her levir, it is a disadvantage, and we do not impose disadvantages on behalf when not in front of them?
He said to him: We have learned it: "And we worry for her words and so she performs chalitza but not yibbum" {thus, in some cases she hates him and in some she loves him, so it is a chov}
Ravina said to Rava: If one gave over a get {to an agent on behalf of his wife, but he appointed this agent rather than she} in case of discord {between them}, what {is the law}? Since there is discord with him, it is a benefit to her? Or perhaps, an easier physical state {for she is being supported, or is gratifying bodily desires} is better for her?
Come and hear {a proof}: For Rabbi Shimon ben Lakish said: It is better to live as two {alternatively, in grief} than to live in widowhood.
END PEREK

BEGIN PEREK SIXTEEN
{Yevamot 119a}
Mishna:

האשה שהלך בעלה וצרתה למדינת הים ובאו ואמרו לה מת בעליך הרי זו לא תנשא ולא תתיבם עד שתדע שמא מעוברת היא צרתה
היתה לה חמות אינה חוששת יצאה מלאה חוששת רבי יהושע אומר אינה חוששת

A woman whose husband and rival went to an overseas country, and they {people} came and said to her "your husband died," she may not remarry nor undergo yibbum, until she ascertains whether her rival is pregnant.
If she had a mother-in-law {overseas}, she need not worry {that the mother-in-law became pregnant with a levir}.
If she {the mother-in-law} went out full {pregnant}, she {the widow} needs to worry. Rabbi Yehoshua says: she does not need to worry.