Is my request to give thank-you cards to my male colleagues who helped me at university considered impermissible (haram), even though the cards contain nothing more than words of thanks?

Expressing gratitude to someone who has shown you kindness is commendable, and there is no religious prohibition against doing so verbally or in writing, provided it adheres to the parameters of Islamic law. As for requesting the presence of the suitor when delivering letters of thanks, this is not forbidden, while keeping in mind that the suitor is a stranger to his fiancée before the marriage contract.