As there is no "gift tax" in Canada any resident of Canada who receives a gift or inheritance of any amount from almost any source (except an employer) will not have to include this in their income.
If the gift is a "Capital Property" and your wife sells it, she will have to pay capital gains on the difference between the value when received and when sold.
If Capital Property (e.g. real estate, investments) is given as a gift, the person who has given the gift will be deemed to have sold the capital property at Fair Market Value (FMV) and will have to pay tax on any resulting capital gains.