I found a good detailed response regarding TRV acceptance.
In reaching a decision whether you are elligible for a visa, the visa officer considers several factors, which include:
* the applicant's travel and identity documents;
* the reason for travel to Canada and the applicant's contacts there;
* the applicant's financial means for the trip;
* the applicant's ties to his or her country of residence, including immigration status, employment and family ties;
* whether the applicant would be likely to leave Canada at the end of the authorized stay;
* the applicant's health condition.
Officers make decisions on a case-by-case basis. The onus is on applicants to show that their intentions are genuine.
Other requirements may include:
1. Completed “Application for a Temporary Resident Visa” (IMM 5257). Accompanying children aged 18 years old and above must complete their own application form.
2. Completed “Family Composition Information and Details of Education and Employment” form for the applicant and each accompanying family member who are aged 18 years old and above, completed in English or French AND YOUR countries language
3. Three (3) identical photos of the applicant and each accompanying family member, colour or black and white taken against a plain white or light coloured background within the last 6 months. The frame size is 35mm X 45mm. On the back of one photo in each set, write the name in pinyin and date of birth (day/month/year) of the person appearing in the photo.
4. A valid passport for the applicant and each accompanying family member. There must be one completely blank page other than the last page, available in each passport and each passport must be valid for at least six (6) months prior to travel
5. Two (2) self-addressed adhesive labels with the applicant's current address
If you are employed, a signed original letter on company letterhead from the employer granting leave of absence and including the following information:
• the applicant's name, position, current salary and date of hire; and
• the employer's name and address in Chinese characters as well as the telephone and fax number.
10. If you are retired, a Retirement Certificate indicating the amount of the applicant's pension.
11. If you are a student traveling during periods other than school holidays, an original letter from your school confirming that you are enrolled and in good standing and that the school has approved your absence.
12. Original bank documents showing financial history over several months (e.g. Certificates of Deposits, bank books, etc.).
13. Evidence of assets your country (e.g. original house property certificate, vehicle registration, etc.).
14. Proof of relationship with the inviter in Canada (e.g. copy of birth certificate, copy of marriage certificate, proof of correspondence, photos, emails etc.)
15. An invitation letter stating the purpose and duration of the visit. This letter should be original and sent in the mail to the applicant in your country. This has more leverage then just writing a letter, signing it, scanning it and sending it via email to the applicant. If possible for the INVITER to write on the letter that he/she will provide all expenses to the applicant, that would be good. But the applicant STILL has to provide his/her own financial proof that would be enough in case of emergency.
16. A list showing the number of people in inviter's household.
17. A copy of the inviter's citizenship (eg. Birth certificate and passport)
18. Proof of inviter's income and financial situation in the form of independent, third-party documentation from a Canadian source which is reliable or easily verifiable. For example, but not limited to: Canada Revenue Agency Notice of Assessments [NOA], employment letters showing salary, pay stubs, banks statements, Statements of Remuneration Paid or financial statements prepared by a licensed professional.