Entertaining multiple goals (makes / make) a person’s life stressful?

Solution 1:

Hmm. All the answers are already in your question (plus you said Singular "make"), so I suppose there's one basic thing you don't understand.

In English, this is a Singular Noun: "student." This is a Plural Noun: "students"

On the other hand, this is a Singular Verb: "makes." And this is a Plural Verb: "make."

Therefore, we always say:

1. The student makes something.

2. The students make something.

Solution 2:

“Entertaining multiple goals” and “To plan road trips” are both singular phrases and both 3rd person 'it', hence he/she/it 'makes' or he/she/it 'involves'.