Did Vinata have any doubts about the outcome of her bet with Kadru in the Mahabharata? Did she innocently consider herself the loser?
Did Vinata have any doubts about the outcome of her bet with Kadru?
No Vinita did not had full doubts about the outcome of her bet with Kadru about the tail of the horse Uchchaihshravas , which came out from churning of ocean. In Fact she herself somewhat confidently said to Kadru this which is mentioned in Astika Parva -SECTION XX of Mahabharata.
शवेत एवाश्वराजॊ ऽयं किं वा तवं मन्यसे शुभे |
बरूहि वर्णं तवम अप्य अस्य ततॊ ऽतर विपणावहे ||3||
śveta evāśvarājo 'yaṃ kiṃ vā tvaṃ manyase śubhe
brūhi varṇaṃ tvam apy asya tato 'tra vipaṇāvahe
And Vinata answered, 'That prince of steeds is certainly white. What dost thou think, sister? Say thou what is its colour. Let us lay a wager upon it.
This shows that she was certain /confident about the color of the horse in some way . As She was ready to lay a wager (an agreement in which people try to guess what will happen and the person who guesses wrong has to give something (such as money) to the person who guesses right.)
The next verse shows us that Vinita Was somewhat confident about the outcome , as she also accepted the term "she who loose will become the slave other's". She wouldn't have accepted this proposal by Kadru , if she was not in someway was sure about the color of the tail.
एवं ते समयं कृत्वा दासी भावाय वै मिथः |
जग्मतुः सवगृहान एव शवॊ दरक्ष्याव इति सम ह ||5||
evaṃ te samayaṃ kṛtvā dāsī bhāvāya vai mithaḥ
jagmatuḥ svagṛhān eva śvo drakṣyāva iti sma ha
'Thus wagering with each other about menial service as a slave, the sisters went home, and resolved to satisfy themselves by examining the horse next day.
Actually the Uchchaihshravas Horse was completely white in color including his tail. This is confirmed from Mahabharata as well as from other puranas.
Did she innocently consider herself the loser?
No , Even though she was somewhat confident and might have seen the horse while it was coming out of ocean , She and kadru both themselves saw the tail of the horse (which was although originally white , but was looking black covered by the snakes) with their own eyes.As told in Astika Parva -SECTION XXIII.
तं समुद्रम अतिक्रम्य कद्रूर विनतया सह |
नयपतत तुरगाभ्याशे नचिराद इव शीघ्रगा||1||
निशाम्य च बहून वालान कृष्णान पुच्छं समाश्रितान|
विनतां विषण्णवदनां कद्रूर दास्ये नययॊजयत||2||
ततः सा विनता तस्मिन पणितेन पराजिता|
अभवद दुःखसंतप्ता दासी भावं समास्थिता||3||
taṃ samudram atikramya kadrūr vinatayā saha
nyapatat turagābhyāśe nacirād iva śīghragā
niśāmya ca bahūn vālān kṛṣṇān pucchaṃ samāśritān
vinatāṃ viṣaṇṇavadanāṃ kadrūr dāsye nyayojayat
tataḥ sā vinatā tasmin paṇitena parājitā
abhavad duḥkhasaṃtaptā dāsī bhāvaṃ samāsthitā
Sauti said, 'Having crossed the Ocean, Kadru of swift speed, accompanied by Vinata, soon alighted near the horse. They then both beheld that foremost of steeds of great speed, with body white as the rays of the moon but having black hairs (in the tail). And observing many black hairs in the tail, Kadru put Vinata, who was deeply dejected, into slavery. And thus Vinata having lost the wager, entered into a state of slavery and became exceedingly sorry.
So from the description given in the verses about her state of mind at that time , we can say that she was in great greef at that time ,when she saw the black tail ,she was sad and depressed; dispirited. But as per wager ,she accepted to be slave of Kadru .
We can also say that she felt the great shock so due to that she was unable to argue about ,what might she already saw or what she was knowing. So we can say that she did not considered herself looser at all but she was also meantime were enable to do anything about the fact or the situation before her, so she accepted the bet forcefully due to situation and from very much sadness. She was helpless at that time.